Add JSON-RPC protocol

[lexburner]

What is the purpose of the change

add a new protocol JSON-RPC. The changes were moved from the origin repository: https://github.com/apache/incubator-dubbo-rpc-jsonrpc

[codecov-io]

Codecov Report

Merging #3786 into master will decrease coverage by 0.09%.
The diff coverage is 45.45%.

@@             Coverage Diff             @@
##             master    #3786     +/-   ##
===========================================
- Coverage     63.58%   63.48%   -0.1%     
  Complexity       71       71             
===========================================
  Files           704      705      +1     
  Lines         31063    31131     +68     
  Branches       5037     5048     +11     
===========================================
+ Hits          19751    19765     +14     
- Misses         9037     9087     +50     
- Partials       2275     2279      +4

Impacted Files	Coverage Δ	Complexity Δ
...ava/org/apache/dubbo/config/ApplicationConfig.java	95.34% <33.33%> (-2.25%)	0 <0> (ø)
...he/dubbo/rpc/protocol/jsonrpc/JsonRpcProtocol.java	46.03% <46.03%> (ø)	0 <0> (?)
.../remoting/transport/netty4/NettyServerHandler.java	61.9% <0%> (-9.53%)	0% <0%> (ø)
...ng/transport/dispatcher/all/AllChannelHandler.java	51.42% <0%> (-5.72%)	0% <0%> (ø)
.../org/apache/dubbo/remoting/ExecutionException.java	15.78% <0%> (-5.27%)	0% <0%> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	57.64% <0%> (-4.71%)	0% <0%> (ø)
.../apache/dubbo/remoting/transport/AbstractPeer.java	63.04% <0%> (-4.35%)	0% <0%> (ø)
.../src/main/java/org/apache/dubbo/rpc/RpcResult.java	94.11% <0%> (-2.76%)	0% <0%> (ø)
...exchange/support/header/HeaderExchangeHandler.java	59.84% <0%> (-2.37%)	0% <0%> (ø)
...he/dubbo/registry/multicast/MulticastRegistry.java	67.87% <0%> (-1.81%)	0% <0%> (ø)
... and 5 more

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[ralf0131]

What is the LICENSE of your dependencies? Could you please list them?

[lexburner]

The JSON-RPC moudle dependends on the jsonrpc4j

<groupId>com.github.briandilley.jsonrpc4j</groupId>
<artifactId>jsonrpc4j</artifactId>
<version>1.2.0</version>

and its license is MIT

<licenses>
	<license>
		<name>The MIT License (MIT)</name>
		<url>http://opensource.org/licenses/MIT</url>
		<distribution>repo</distribution>
	</license>
</licenses>

[ralf0131]

LGTM! Thanks for the pull request.