Saves about 473 byte of progmem and 28 bytes of RAM.

Uses about 488 byte of progmem and 32 byte of RAM.
For that configurable.

- For some reason it’s easy to forget what BT stands for, but it
doesn’t need an abbreviation.

- The default serial baud rate of 115200
- The regular RigitBot bed size 254mm/248mm/254mm
- Single stock extruder
- Stock termistors for extruder and hotbed
- Stock Min X/Y/Z stops. Max stops not connected
- Stock 32 teth tooleys (stock axis steps)
- No auto bed leveling
- No screen

For consistency with other pins, allowing use of `PIN_EXISTS` macro.

- `SD_DETECT_PIN` replaces `SDCARDDETECT`
- `SD_DETECT_INVERTED` replaces `SDCARDDETECTINVERTED`
- Revise the description of `SD_DETECT_INVERTED`
- Add a note about the override of `SD_DETECT_INVERTED` in
`Conditionals.h`

- Rename the pin so it can be tested with `PIN_EXISTS`
- Fix some incorrect tests for `SDCARDDETECT`

For consistency with other pins, allowing use of `PIN_EXISTS` macro.

Apply `ENABLED` / `DISABLED` macros to files needing only a small
number of changes.

Apply `ENABLED` / `DISABLED` macros to EEPROM-related files.

Apply `ENABLED` / `DISABLED` macros to planner files.

Apply `ENABLED` / `DISABLED` macros to temperature-related files.

Apply `ENABLED` / `DISABLED` macros to stepper-related files.

Apply `ENABLED` / `DISABLED` macros to LCD-related files.

Apply `ENABLED` / `DISABLED` / `HAS_SERVOS` macros to pins files.

Apply `ENABLED` / `DISABLED` macros to language-related files.