[Keyboard] Add "Selene" to the handwired section (#9920)

* Added handwired/selene based on handwired/106_with_trackpoint

* now at least parially working

* Selene Firmware 1, ready

* Updated Readme to align more with Template

* Added URL to info.json

* Fix status Lights being wired incorrectly

* Update keyboards/handwired/selene/config.h

* Update keyboards/handwired/selene/keymaps/Bpendragon/keymap.c

* Update keyboards/handwired/selene/selene.c

* Update keyboards/handwired/selene/selene.h

* Changes for PR requested by fauxpark

* Adds `default` keymap
* Renames `Bpendragon` to `bpendragon`
* Removes uneeded descriptors and options
* Simplifies return statement in `keymap.c`
* Removes trailing slashes from layout in `keymap.c`
* Updates `readme.mk` to reflect default keymap
* Aligns comments in `rules.mk`

* Forced folder name update to lowercase

* Apply suggestions from code review

keyboards/handwired/selene/rules.mk

@@ -0,0 +1,20 @@
+# MCU name
+MCU = STM32F303
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = lite     # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = no        # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = yes        # Console for debug
+COMMAND_ENABLE = yes        # Commands for debug and configuration
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
+# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+NKRO_ENABLE = yes           # USB Nkey Rollover
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+WS2812_DRIVER = bitbang
+BLUETOOTH_ENABLE = no       # Enable Bluetooth
+AUDIO_ENABLE = no           # Audio output