[Keymap] Added my customized 40% layout (#7555)

* Formatting of Contra readme.

* Initial version of my custom keymap

* Move TODOs to readme

* Add comment

* Nuke Plover layer

* Port changes to other layers

* Finished work on my own layout for now

* Add layout image

* Processed comments from review

keyboards/contra/keymaps/alper/config.h

@@ -0,0 +1,38 @@
+#pragma once
+
+
+#ifdef AUDIO_ENABLE
+    #define STARTUP_SONG SONG(PLANCK_SOUND)
+    // #define STARTUP_SONG SONG(NO_SOUND)
+
+    #define DEFAULT_LAYER_SONGS { SONG(QWERTY_SOUND), \
+                                  SONG(COLEMAK_SOUND), \
+                                  SONG(DVORAK_SOUND) \
+                                }
+#endif
+
+#define MUSIC_MASK (keycode != KC_NO)
+
+/*
+ * MIDI options
+ */
+
+/* Prevent use of disabled MIDI features in the keymap */
+//#define MIDI_ENABLE_STRICT 1
+
+/* enable basic MIDI features:
+   - MIDI notes can be sent when in Music mode is on
+*/
+
+#define MIDI_BASIC
+
+/* enable advanced MIDI features:
+   - MIDI notes can be added to the keymap
+   - Octave shift and transpose
+   - Virtual sustain, portamento, and modulation wheel
+   - etc.
+*/
+//#define MIDI_ADVANCED
+
+/* override number of MIDI tone keycodes (each octave adds 12 keycodes and allocates 12 bytes) */
+//#define MIDI_TONE_KEYCODE_OCTAVES 2