[Keymap] Yet another xd75 keymap (#6734)

* add a keymap for xd75

* add colors, change some keys, add reactive modifier hold, key press

* add readme

* permissive hold

keyboards/xd75/keymaps/xo/rules.mk

@@ -0,0 +1,14 @@
+# 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 3 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 <https://www.gnu.org/licenses/>.
+
+BACKLIGHT_ENABLE = yes