LFKeyboards Mini1800: refactor into revisions (#16260)

* fork Mini1800 into reva and revc versions

* update info.json

- apply friendly formatting
- update maintainer value

* update keymap rules.mk formatting

- align inline comments
- convert tabs to spaces

* align keymap rules.mk files to QMK template

* move common keymap rules.mk settings to revision level

* info.json: correct key sequence

* align revision rules.mk files to QMK template

* clean up revision rules.mk files

* add readme files for each revision

* correct USB Product string

* remove post_rules.mk files

The internal settings were commented out, so the files actually don't do anything.

* edit Bootloader instructions on main readme

* move non-assignment rules to post_rules.mk

* add inline comments for NKRO_ENABLE per fauxpark

keyboards/lfkeyboards/mini1800/keymaps/ca178858/rules.mk

@@ -1,45 +1 @@
-BOOTMAGIC_ENABLE = no       # Enable Bootmagic Lite
-MOUSEKEY_ENABLE = no            # Mouse keys(+4700)
-EXTRAKEY_ENABLE = yes           # Audio control and System control(+450)
-CONSOLE_ENABLE = no             # Console for debug(+400)
-COMMAND_ENABLE = no             # Commands for debug and configuration
-NKRO_ENABLE = yes
-BACKLIGHT_ENABLE = yes           # Enable keyboard backlight functionality
-MIDI_ENABLE = no                # MIDI controls
-AUDIO_ENABLE = yes              # Audio output on port C6
-UNICODE_ENABLE = no             # Unicode
-BLUETOOTH_ENABLE = no           # Enable Bluetooth with the Adafruit EZ-Key HID
-RGBLIGHT_ENABLE = yes           # Enable RGB underlight
-RGBLIGHT_CUSTOM_DRIVER = yes    # RGB code is implemented in lefkeyboards, not WS2812
-SLEEP_LED_ENABLE = yes
 TAP_DANCE_ENABLE = yes
-
-ISSI_ENABLE = yes			# If the I2C pullup resistors aren't install this must be disabled
-WATCHDOG_ENABLE = yes		# Resets keyboard if matrix_scan isn't run every 250ms
-
-
-
-ifeq ($(strip $(ISSI_ENABLE)), yes)
-    TMK_COMMON_DEFS += -DISSI_ENABLE
-endif
-
-ifeq ($(strip $(WATCHDOG_ENABLE)), yes)
-    TMK_COMMON_DEFS += -DWATCHDOG_ENABLE
-endif
-
-
-# # Set the LFK78 hardware version. This is defined in rules.mk, but can be overidden here if desired
-# #
-# # RevB - first public release, uses atmega32u4, has audio, ISSI matrix split between RGB and backlight
-# # RevC/D - at90usb1286, no audio, ISSI device 0 is backlight, 4 is RGB
-# #
-# # Set to B, C or D
-# LFK_REV = D
-
-# ifeq ($(LFK_REV), B)
-# 	MCU = atmega32u4
-# else
-# 	MCU = at90usb1286
-# endif
-# OPT_DEFS += -DLFK_REV_$(LFK_REV)
-# OPT_DEFS += -DUSB_PRODUCT=\"LFK_Rev$(LFK_REV)\"