Rearrange code in InetInterface

[kpschoedel]

Problem

Code for different Inet implementations is scattered across many #ifs.

Change overview

• Groups code by implementation.
• Moves doxygen comments to the header.

Since comparing moved code in diff format is difficult, this change
explicitly does NOT make any changes to function bodies, with one
exception: incorporating the CloseIOSocket() bug fix from PR#10452
to avoid conflicts.

This is a step toward #7715 Virtualize System and Inet interfaces.

Testing

CI; no change to functionality.

[github-actions]

PR #10502: Size comparison from a654c82 to baf3ff4

24 builds

platform	target	config	section	a654c82	baf3ff4	change	% change
efr32	lighting-app	BRD4161A	.bss	118004	118004	0	0.0
			.data	1800	1800	0	0.0
			.text	780924	780924	0	0.0
	lock-app	BRD4161A	.bss	115876	115876	0	0.0
			.data	1760	1760	0	0.0
			.text	760172	760172	0	0.0
	window-app	BRD4161A	.bss	116196	116196	0	0.0
			.data	1764	1764	0	0.0
			.text	761088	761088	0	0.0
	lighting-app	BRD4161A+rpc	.bss	131332	131332	0	0.0
			.data	1852	1852	0	0.0
			.text	760656	760656	0	0.0
esp32	all-clusters-app	c3devkit	.dram0.bss	60248	60248	0	0.0
			.dram0.data	16232	16232	0	0.0
			.flash.rodata	198144	198144	0	0.0
			.flash.text	868962	868962	0	0.0
			.iram0.text	57330	57330	0	0.0
		m5stack	.dram0.bss	62752	62752	0	0.0
			.dram0.data	32084	32084	0	0.0
			.flash.rodata	206732	206732	0	0.0
			.flash.text	900095	900003	-92	-0.0
			.iram0.text	125115	125115	0	0.0
k32w	lock-app	k32w061+debug	.bss	69036	69036	0	0.0
			.data	1864	1864	0	0.0
			.text	514056	514056	0	0.0
	shell	k32w061+debug	.bss	55080	55080	0	0.0
			.data	672	672	0	0.0
			.text	356808	356808	0	0.0
	lighting-app	k32w061+se05x+release	.bss	78552	78552	0	0.0
			.data	1900	1900	0	0.0
			.text	612732	612732	0	0.0
linux	all-clusters-app	debug	.bss	52144	52144	0	0.0
			.data	978	978	0	0.0
			.data.rel.ro	58352	58352	0	0.0
			.dynamic	592	592	0	0.0
			.got	4072	4072	0	0.0
			.init	27	27	0	0.0
			.init_array	512	512	0	0.0
			.rodata	134773	134773	0	0.0
			.text	1318226	1318274	48	0.0
	chip-tool	debug	.bss	17584	17584	0	0.0
			.data	1584	1584	0	0.0
			.data.rel.ro	77392	77392	0	0.0
			.dynamic	592	592	0	0.0
			.got	4328	4328	0	0.0
			.init	27	27	0	0.0
			.init_array	416	416	0	0.0
			.rodata	173664	173664	0	0.0
			.text	2425109	2425157	48	0.0
	ota-provider-app	debug	.bss	37472	37472	0	0.0
			.data	752	752	0	0.0
			.data.rel.ro	23112	23112	0	0.0
			.dynamic	592	592	0	0.0
			.got	4008	4008	0	0.0
			.init	27	27	0	0.0
			.init_array	448	448	0	0.0
			.rodata	108824	108824	0	0.0
			.text	1005410	1005458	48	0.0
	ota-requestor-app	debug	.bss	205728	205728	0	0.0
			.data	752	752	0	0.0
			.data.rel.ro	24408	24408	0	0.0
			.dynamic	592	592	0	0.0
			.got	4136	4136	0	0.0
			.init	27	27	0	0.0
			.init_array	520	520	0	0.0
			.rodata	126864	126864	0	0.0
			.text	1125042	1125090	48	0.0
	shell	debug	.bss	16104	16104	0	0.0
			.data	242	242	0	0.0
			.data.rel.ro	35184	35184	0	0.0
			.dynamic	592	592	0	0.0
			.got	3504	3504	0	0.0
			.init	27	27	0	0.0
			.init_array	344	344	0	0.0
			.rodata	71343	71343	0	0.0
			.text	574322	574386	64	0.0
	tv-app	debug	.bss	216368	216368	0	0.0
			.data	2032	2032	0	0.0
			.data.rel.ro	55536	55536	0	0.0
			.dynamic	592	592	0	0.0
			.got	4408	4408	0	0.0
			.init	27	27	0	0.0
			.init_array	616	616	0	0.0
			.rodata	150536	150536	0	0.0
			.text	1463730	1463778	48	0.0
	bridge-app	debug+rpc	.bss	52880	52880	0	0.0
			.data	976	976	0	0.0
			.data.rel.ro	25480	25480	0	0.0
			.dynamic	592	592	0	0.0
			.got	3944	3944	0	0.0
			.init	27	27	0	0.0
			.init_array	408	408	0	0.0
			.rodata	109492	109492	0	0.0
			.text	1047493	1047541	48	0.0
	lighting-app	debug+rpc	.bss	42200	42200	0	0.0
			.data	1106	1106	0	0.0
			.data.rel.ro	52192	52192	0	0.0
			.dynamic	608	608	0	0.0
			.got	4104	4104	0	0.0
			.init	27	27	0	0.0
			.init_array	536	536	0	0.0
			.rodata	126641	126641	0	0.0
			.text	1248642	1248706	64	0.0
mbed	lighting-app	CY8CPROTO_062_4343W+release	.bss	172132	172132	0	0.0
			.data	5464	5464	0	0.0
			.heap	858848	858848	0	0.0
			.text	1218656	1218720	64	0.0
	lock-app	CY8CPROTO_062_4343W+release	.bss	171068	171068	0	0.0
			.data	5432	5432	0	0.0
			.heap	859944	859944	0	0.0
			.text	1196648	1196712	64	0.0
p6	lock-app	default	.bss	68208	68208	0	0.0
			.data	2416	2416	0	0.0
			.heap	962720	962720	0	0.0
			.text	1124840	1124840	0	0.0
qpg	lighting-app	qpg6100+debug	.bss	53520	53520	0	0.0
			.data	996	996	0	0.0
			.text	485252	485252	0	0.0
	lock-app	qpg6100+debug	.bss	52472	52472	0	0.0
			.data	952	952	0	0.0
			.text	461436	461436	0	0.0
	persistent-storage-app	qpg6100+debug	.bss	17778	17778	0	0.0
			.data	280	280	0	0.0
			.text	102704	102704	0	0.0
telink	lighting-app	tlsr9518adk80d	bss	70972	70972	0	0.0
			noinit	33216	33216	0	0.0
			text	457428	457428	0	0.0

10 builds

platform	target	config	section	a654c82	baf3ff4	change	% change
nrfconnect	lighting-app	nrf52840dk_nrf52840	bss	112304	112304	0	0.0
			rodata	97160	97160	0	0.0
			text	576856	576856	0	0.0
	lock-app	nrf52840dk_nrf52840	bss	111336	111336	0	0.0
			rodata	93656	93656	0	0.0
			text	558300	558300	0	0.0
	pigweed-app	nrf52840dk_nrf52840	bss	51772	51772	0	0.0
			rodata	45772	45772	0	0.0
			text	339392	339392	0	0.0
	pump-app	nrf52840dk_nrf52840	bss	111404	111404	0	0.0
			rodata	94640	94640	0	0.0
			text	561468	561468	0	0.0
	pump-controller-app	nrf52840dk_nrf52840	bss	111344	111344	0	0.0
			rodata	93716	93716	0	0.0
			text	558076	558076	0	0.0
	shell	nrf52840dk_nrf52840	bss	107320	107320	0	0.0
			rodata	71336	71336	0	0.0
			text	518964	518964	0	0.0
	lighting-app	nrf52840dk_nrf52840+rpc	bss	108544	108544	0	0.0
			rodata	87940	87940	0	0.0
			text	550060	550060	0	0.0
		nrf5340dk_nrf5340_cpuapp	bss	113676	113676	0	0.0
			rodata	92400	92400	0	0.0
			text	506316	506316	0	0.0
	lock-app	nrf5340dk_nrf5340_cpuapp	bss	112708	112708	0	0.0
			rodata	88916	88916	0	0.0
			text	487752	487752	0	0.0
	shell	nrf5340dk_nrf5340_cpuapp	bss	108304	108304	0	0.0
			rodata	65980	65980	0	0.0
			text	439564	439564	0	0.0