Cleanup rules.mk for 32U4 keyboards, L-M (#7120)

* Cleanup rules.mk for 32U4 keyboards, L-M

* Move some stuff to keyboard level

keyboards/maxr1998/phoebe/rules.mk

@@ -1,10 +1,14 @@
 # MCU name
 MCU = atmega32u4
 
-# Bootloader
-#     This definition is optional, and if your keyboard supports multiple bootloaders of
-#     different sizes, comment this out, and the correct address will be loaded
-#     automatically (+60). See bootloader.mk for all options.
+# Bootloader selection
+#   Teensy       halfkay
+#   Pro Micro    caterina
+#   Atmel DFU    atmel-dfu
+#   LUFA DFU     lufa-dfu
+#   QMK DFU      qmk-dfu
+#   ATmega32A    bootloadHID
+#   ATmega328P   USBasp
 BOOTLOADER = atmel-dfu
 
 # Build Options
@@ -27,4 +31,3 @@ RGBLIGHT_ENABLE = yes      # Enable WS2812 RGB underlight.
 KEY_LOCK_ENABLE = yes
 API_SYSEX_ENABLE = no
 SLEEP_LED_ENABLE = no      # Breathing sleep LED during USB suspend
-