[Keymap] rootiest for planck/rev6/ (#13294)

* squashed commits to master

* Fix in case of missing user_song_list
Substitutes missing songs with safe versions
Also updated and added detail to keymap readme

* Adjust Readme to match qmk contrib conventions

* Update keyboards/planck/keymaps/rootiest/config.h

* Update keyboards/planck/keymaps/rootiest/keymap.c

* Update keyboards/planck/keymaps/rootiest/keymap.c

* Update keyboards/planck/keymaps/rootiest/keymap.c

* Update keyboards/planck/keymaps/rootiest/keymap.c

* Fixed license header to GPLv2+

* Fix Volume key delay
Use a static number instead of removed MEDIA_KEY_DELAY

* Use TAP_CODE_DELAY

* added license to config.h

* Clean up formatting
- Fixed markdown in readme
- Removed extra commented line from config.h

* Update keyboards/planck/keymaps/rootiest/config.h

keyboards/planck/keymaps/rootiest/rules.mk

@@ -0,0 +1,26 @@
+SRC += muse.c
+ENCODER_ENABLE = yes # Enables basic encoder support
+OLED_DRIVER_ENABLE = yes # Enables support for OLED displays
+# UNICODE_ENABLE = yes # Allow inputting basic unicode characters
+UNICODEMAP_ENABLE = yes # Enable use of Unicode mapping array
+# UCIS_ENABLE = yes # Another method for generating Unicode characters via maps
+TAP_DANCE_ENABLE = yes # Enable Tap-Dance
+NKRO_ENABLE = yes # Enable N-Key rollover
+MOUSEKEY_ENABLE = yes # Enable mouse emulation
+EXTRAKEY_ENABLE = yes # Allows audio control and System control
+RAW_ENABLE = yes # Enable bi-directional communication to host
+CONSOLE_ENABLE = yes # Enable outputting debugging data/logs to terminal
+WPM_ENABLE = yes # Enable on-board words-per-minute tracking
+VELOCIKEY_ENABLE = yes # Enables dynamically changing rgb animation speed based on WPM
+LEADER_ENABLE = yes # Enables Leader-Key
+COMBO_ENABLE = yes # Enables combo keys
+KEY_LOCK_ENABLE = yes # Enables using lock key to maintain holds
+# LTO_ENABLE = yes # Does some optimisation to make firmware size smaller
+# SWAP_HANDS_ENABLE = yes # Enables the swap hands function
+# DEBOUNCE_TYPE = sym_eager_pk # Change debounce algorithm
+
+# NOTE: The following requires a lot of memory to include
+TERMINAL_ENABLE = yes # Enables a command-line-like interface designed to communicate through a text editor with keystrokes
+
+# NOTE: The following is not yet available in main qmk branch
+KEY_OVERRIDE_ENABLE = yes # Allows overiding modifier combos (change Shift+1 without affecting 1 or Shift's normal operation)