Added VT-40 keyboard (#24706)

* Added VT-40 keyboard

* Remove commented out code. Oops

Co-authored-by: jack <jack@pngu.org>

* Change name of planck_layers to layers.

Co-authored-by: jack <jack@pngu.org>

* Update keyboards/vt40/keymaps/default/keymap.c

Co-authored-by: jack <jack@pngu.org>

* Removed unused features that I stole from the contra config

* Removed unused features that I stole from the contra config

* fixed lower/raise keys

* make adjust layer accessible

* Added adjust key for real this time

* Update keyboards/vt40/keyboard.json

Co-authored-by: Duncan Sutherland <dunk2k_2000@hotmail.com>

---------

Co-authored-by: jack <jack@pngu.org>
Co-authored-by: Duncan Sutherland <dunk2k_2000@hotmail.com>

keyboards/vt40/readme.md

@@ -0,0 +1,24 @@
+# VT-40
+
+* Keyboard Maintainer: [Guido Bartolucci](https://github.com/guidoism)
+* Hardware Supported: Raspberry Pi Pico (RP2040)
+* Hardware Availability: https://github.com/vladantrhlik/VT-40
+
+Make example for this keyboard (after setting up your build environment):
+
+    make vt40:default
+
+Flashing example for this keyboard:
+
+    make vt40: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**: Briefly press the button on the back of the PCB - some may have pads you must short instead
+* **Keycode in layout**: Press the key mapped to `QK_BOOT` if it is available
+