[Keymap] bcat keymaps and userspace (#10705)

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* Remove outdated Crkbd Ctrl key positioning info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* Update outdated reference to Crkbd layout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

keyboards/lily58/keymaps/bcat/readme.md

@@ -1,8 +1,8 @@
 # bcat's Lily58 layout
 
-This split ergo layout follows my preferred [Crkbd
-layout](https://github.com/qmk/qmk_firmware/tree/master/keyboards/crkbd/keymaps/bcat)
-with the following changes:
+This split ergo layout follows my preferred [split 3x6 + 3 thumb
+keys](https://github.com/qmk/qmk_firmware/tree/master/layouts/community/split_3x6_3/bcat)
+(Crkbd) layout with a few changes:
 
 * There's an optional number row at the top of the keyboard. I am quite used to
 using layers for numbers and symbols, so in practice this goes unused.
@@ -11,12 +11,15 @@ using layers for numbers and symbols, so in practice this goes unused.
 placed in the same positions as on the ErgoDox EZ. (There's no real reason for
 this; I just had to do _something_ with those keys.)
 
-* The extra thumb keys are used for dedicated Super/Menu keys, as well as
-browser back/forward navigation keys.
+* The extra thumb keys on the bottom row are used for a Left Alt key (for easier
+Alt+Tab, Alt+F4, etc.) and a dedicated Super key.
+
+* The harder-to-reach thumb keys below the controllers are bound to browser
+back/forward navigation keys.
 
 ## Default layer
 
-![Default layer layout](https://i.imgur.com/FNITWJ0.png)
+![Default layer layout](https://i.imgur.com/0stG2GT.png)
 
 ([KLE](http://www.keyboard-layout-editor.com/#/gists/e0eb3af65961e9fd612dcff3ddd88e4f))