Updates to Ploopy Classic, Mouse, and Thumb for RP2040 hardware upgrade

[ploopyco]

Description

The Ploopy Mouse, Thumb, and Classic are all being upgraded from their original MCU architecture (ATmega32u4) to a new MCU architecture (RP2040). These new firmwares have all been tested and are currently being distributed.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• None.

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[drashna]

Default folder is going away in the near future.

This file should probably be renamed to post_rules.mk

Suggested change

	DEFAULT_FOLDER = ploopyco/mouse/rev1_003

[ploopyco]

I can rename it to post_rules.mk. I can also rename keyboards/ploopyco/trackball_thumb/rules.mk to keyboards/ploopyco/trackball_thumb/post_rules.mk, if you think that makes sense.

[ploopyco]

Removing the DEFAULT-FOLDER lines caused a bunch of lint and CI failures. I added it back in with #f51e9f1 so that the lint and CI checks pass, but I'm open to reorganizing things if that's better.

[drashna]

Yeah, if there is a rules.mk file, the build system (and CI) considers it to be a valid keyboard folder. In this case, .... it's not. Moving/renaming the file would probably be the best option.