[Keyboard] Add "Uno" rev2 (#14071)

* [Keyboard] Add "Uno" rev2

Adds support for the second revision of Uno, courtesy of @Snipeye.

* Update keyboards/uno/rev2/rules.mk

* Update keyboards/uno/rev1/rules.mk

* Update keyboards/uno/uno.h

* Update keyboards/uno/rev2/rules.mk

* Update keyboards/uno/rev1/rules.mk

* Update keyboards/uno/keymaps/demo/keymap.c

* Update keyboards/uno/keymaps/demo/keymap.c

* Update keyboards/uno/keymaps/demo/keymap.c

* Update keyboards/uno/rev2/rules.mk

* Update keyboards/uno/rev1/rules.mk

* Align rules.mk comments

* Update keyboards/uno/info.json

* Update keyboards/uno/rev1/config.h

* Update keyboards/uno/rev2/config.h

* Update keyboards/uno/rev2/config.h

* Update keyboards/uno/rev2/config.h

* Update keyboards/uno/rev1/config.h

keyboards/uno/rules.mk

@@ -1,18 +1 @@
-# MCU name
-MCU = atmega32u4
-
-# Bootloader selection
-BOOTLOADER = caterina
-
-# Build Options
-#   change yes to no to disable
-#
-BOOTMAGIC_ENABLE = yes      # Enable Bootmagic Lite
-MOUSEKEY_ENABLE = yes       # Mouse keys
-EXTRAKEY_ENABLE = yes       # Audio control and System control
-CONSOLE_ENABLE = no         # Console for debug
-COMMAND_ENABLE = no         # Commands for debug and configuration
-NKRO_ENABLE = no            # Enable N-Key Rollover
-BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
-RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
-AUDIO_ENABLE = no           # Audio output
+DEFAULT_FOLDER = uno/rev1