Adding Synth and Keys' Debit Card (#18995)

* Adding Synth and Keys' Debit Card

Initial Commit

* Add files via upload

* Delete config.h

* Update keyboards/synthandkeys/the_debit_card/info.json

Co-authored-by: Joel Challis <git@zvecr.com>

keyboards/synthandkeys/the_debit_card/readme.md

@@ -0,0 +1,27 @@
+# synthandkeys/the_debit_card
+
+![synthandkeys/the_debit_card](https://i.imgur.com/8dpEv73.jpeg)
+
+The Debit Card is a 10-key programmable mechanical keyboard that could fit in your wallet. The ultra-thin, ultra-portable macropad is powered by the XIAO RP2040 and can support KMK, QMK, or VIAL open-source keyboard firmware.
+
+* Keyboard Maintainer: [Synth and Keys](https://github.com/Synth-and-Keys)
+* Hardware Supported: The Debit Card PCB, Seeed XIAO MCU
+* Hardware Availability: https://etsy.me/3UslJQF, https://www.seeedstudio.com/XIAO-RP2040-v1-0-p-5026.html
+
+Make example for this keyboard (after setting up your build environment):
+
+    make synthandkeys/the_debit_card:default
+
+Flashing example for this keyboard:
+
+    make synthandkeys/the_debit_card:default:flash
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+* **Bootmagic reset**: Hold down the key at (0,0) in the matrix (usually the top left key or Escape) and plug in the keyboard
+* **Physical reset button**: Press the button on the Seeed XIAO microcontroller twice.
+* **Keycode in layout**: Press the key mapped to `QK_BOOT` if it is available