Add Eco keymap, factor Crkbd keymap to community layout, other minor tweaks
* Remove outdated Crkbd Ctrl key positioning info
* Add Left Alt key to Lily58 keymap
* Lily58 no longer overrides default TAPPING_TERM
* Refactor Crkbd keymap to use new community layout
* Fix underglow animations for Crkbd w/ Split Common
* Add initial Eco keymap
* Update outdated reference to Crkbd layout
* Add keymap links to userspace readme
* Add copyright notices to files changed in this PR
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