[Keymap] addition for mjuma in keyboards/planck/keymaps (#10885)

* Add planck layout

* switch gaming toggle to TG

* rename readme

keyboards/planck/keymaps/mjuma/config.h

@@ -0,0 +1,28 @@
+/* Copyright 2017-2021 M Juma
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#ifdef AUDIO_ENABLE
+    #define STARTUP_SONG SONG(PLANCK_SOUND)
+
+    #define DEFAULT_LAYER_SONGS { SONG(QWERTY_SOUND), \
+                                  SONG(COLEMAK_SOUND), \
+                                  SONG(DVORAK_SOUND) \
+                                }
+#endif
+
+#define TAPPING_TERM 200