Update outdated documentation

[brainelectronics]

Added

• Installation instructions for mip usage on MicroPython 1.19.1 or newer, see Update documentation for mip usage #44
• Manual testing Dockerfile
• INSTALLATION, TESTING and EXAMPLES files for simpler docs structure

Changed

• Split SETUP into INSTALLATION
• Split USAGE into TESTING and EXAMPLES
• Use callback to reset register data in RTU client example
• Update docs copyright year to 2023
• Use fakes machine module instead of classic Mock in docs config file

Fixed

• Basic RTU host example in root README uses correct init values, optional parameters are listed after mandatory ones
• Remove outdated warning sections about Read/Write register at some location of definition #35 bug from USAGE

[brainelectronics]

Hey @beyonlo and @toddkarin here are the updated beautiful docs. Let me know whether this resolves #54 😃

https://micropython-modbus--55.org.readthedocs.build/en/55/

[brainelectronics]

• :books: emoji is not working in RTD, see https://micropython-modbus--55.org.readthedocs.build/en/55/readme_link.html
• Citations are not rendered properly in https://micropython-modbus--55.org.readthedocs.build/en/55/INSTALLATION.html

[beyonlo]

@brainelectronics

Excellent! I liked it so much! Beautiful docs and very useful 🎉

Some possible suggestions/improvements:

1. On the manually installation, a option is to put a example with mpremote as well, together that rshell example. As mpremote become a standard use, maybe is a good idea. mpremote cp -r umodbus/ :

2. On the Structure, on the ISTS (INPUT STATUS) are using in some comments input registers instead input status or discrete inputs. Shouldn't use input registers to be used just for the IREGS (INPUT REGISTERS)?

A extra note: About that behaviour where the callback print always signed False, maybe a way to solve is to put on the JSON structure a option "signed" [False, True] configured by user, like as the "val" and "len". So the Slave/Client use that to know if print/use signed False or True.