Adding pro-micro support to Desktop & firm

[minchetas]

Issues

• Fixes #
• Resolves #
• Closes #

Description

Add support to Sparkfun PRO Micro boards.

Types of changes

Put an x in the boxes that apply

• [ ] Bugfix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [X] Requested changes are in a branch
• [ ] Compiled and tested requested changes on target hardware (PC, device)
• [ ] Updated the documentation, if necessary
• [ ] Updated the LICENSES file, if necessary
• [ ] Reviewed the guidelines for contributing to this repository

Further comments

• Added new environment in platform.io for pro-micro board
• Defined the ports for the new board in Config.h, selectable by environment variable: -DPRO_MICRO
• Modified desktop software (C#) to fix serial port to detect new device