[Keyboard] XD75 refactor (#5420)

* Refactor layout macro names

Update the names of the layout macros to reflect QMK's desired usage.

- KEYMAP renamed to LAYOUT
  - colinta keymap updated accordingly
- KC_KEYMAP renamed to LAYOUT_kc
  - mtdjr keymap updated accordingly

* Update xd75.h to use #pragma once include guard

* Update keymaps to use QMK_KEYBOARD_H

* Refactor default keymap

- updated to use layout macro
- remove deprecated action_get_macro function
- add functions from QMK keymap.c template
  - process_record_user
  - matrix_init_user
  - matrix_scan_user
  - led_set_user

* Update supporting files

- updated config.h files to use #pragma once include guard
- remove errant QUANTUM_DIR code block

* Rename readme files to fully lowercase filenames

* Restructure keyboard readme

Updated the readme to better align with the current QMK template.

* Bugfixes to supporting files

1 files changed, 13 insertions, 0 deletions

diff --git a/keyboards/xd75/keymaps/developper_bepo/readme.md b/keyboards/xd75/keymaps/developper_bepo/readme.md
new file mode 100644
index 000000000..7954a683a
--- /dev/null
+++ b/keyboards/xd75/keymaps/developper_bepo/readme.md
@@ -0,0 +1,13 @@
+# developper_bepo Custom Keyboard
+
+Layout for Bépo Software development
+
+* Improved access to frequently used keys in software development
+* Modified layout for english input
+* Easy access to layers with space and enter key
+
+Keyboard maintainer: [Quentin Lebastard](https://github.com/lebastaq)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make xd75:developper_bepo