Remove "empty" files

[zvecr]

Description

As part of the pending mass keymap removal, this PR removes a bunch of pointless files that do not need to exist whatever happens.

find keyboards/ -name config.h | grep -v "/keymaps" | xargs grep -L undef | xargs grep -L define | xargs git rm
find keyboards/ -name config.h | grep "/keymaps" | xargs grep -L undef | xargs grep -L define | xargs git rm
find keyboards/ -name rules.mk | grep "/keymaps" | xargs grep -L = | xargs git rm

Types of Changes

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

Issues Fixed or Closed by This PR

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).