Add Libraries for Modbus TCP Communication

[CMB27]

This adds two libraries.

• ModbusTCPComm, is for sending and receiving Modbus data frames over TCP.
• ModbusTCPSlave, depends on the first and implements Modbus slave/server processing for this communication.

[github-actions]

A problem was found with your submission https://github.com/CMB27/ModbusTCPSlave

❌ ERROR: Unable to load submission URL. Is the repository public?

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/CMB27/ModbusTCPComm:

Linting library in ModbusTCPComm
WARNING: library.properties includes field item(s) ModbusADU.h not found in library.                           
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format
         (Rule LP052)                                                                                          
WARNING: No example sketches found. Please provide examples.                                      
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#library-examples
         (Rule LD004)                                                                             

Linter results for project: 0 ERRORS, 2 WARNINGS

-------------------

[github-actions]

Thanks for your interest in contributing to the Arduino Library Manager index @CMB27
Please resolve the error(s) mentioned in the previous comment.

After resolving the issue, trigger this check again by doing one of the following:

• Commit the required change to the branch you submitted this pull request from.
• Comment here, mentioning @ArduinoBot in the comment.

❗ NOTE: It is not necessary to open a new pull request. ❗

More information:
https://github.com/arduino/library-registry/blob/main/README.md#if-the-problem-is-with-the-pull-request

[CMB27]

ModbusTCPSlave was not a public repository when I first submitted this pull request. It has now been changed to a public repository.

@ArduinoBot do your thing.

[github-actions]

Hello! I'm checking your submission again.

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/CMB27/ModbusTCPSlave:

Linting library in ModbusTCPSlave
WARNING: library.properties depends field item(s) ModbusTCPComm (>=0.0.1) not found in the Library Manager index.
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format  
         (Rule LP048)                                                                                            

Linter results for project: 0 ERRORS, 1 WARNINGS

-------------------

Linting sketch in ModbusTCPSlave/examples/ModbusTCPSlaveEthernetExample

Linter results for project: no errors or warnings

-------------------

Linting sketch in ModbusTCPSlave/examples/ModbusTCPSlaveWiFiExample

Linter results for project: no errors or warnings

-------------------

Linter results for projects: 0 ERRORS, 1 WARNINGS

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/CMB27/ModbusTCPComm:

Linting library in ModbusTCPComm
WARNING: library.properties includes field item(s) ModbusADU.h not found in library.                           
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format
         (Rule LP052)                                                                                          
WARNING: No example sketches found. Please provide examples.                                      
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#library-examples
         (Rule LD004)                                                                             

Linter results for project: 0 ERRORS, 2 WARNINGS

-------------------

[github-actions]

Your submission has now been accepted! Thanks for your contribution to the Arduino Library Manager index.

The library(s) will be available for installation via Library Manager within a day's time.

You can check the logs from the Library Manager indexer for your library(s) here:
http://downloads.arduino.cc/libraries/logs/github.com/CMB27/ModbusTCPComm/
http://downloads.arduino.cc/libraries/logs/github.com/CMB27/ModbusTCPSlave/