[Keyboard] Add OSA keyboard (#6849)

* initial commit

restart of osa development

* minor changes

Minor changes
mostly changing naming and comment out rgb modes

* initial commit

restart of osa development

* minor changes

Minor changes
mostly changing naming and comment out rgb modes

* more minor changes

comment out some functions
correct some spelling errors
change some of the descriptive text

* Minor Changes

Minor changers per PR requests

* Minor Changes

Minor changes per PR suggestions

* Major Changes

Per PR suggestion from noroadsleft:

- changed macro to LAYOUT_all in info.json, dualsplit/keymap.c and ocm/keymap.c, and osa.h

- added osa.h macros for other layouts per suggestion and used suggested naming

-  changed naming of layout macros to correspond to macros and naming in default/keymap.c, dualsplit/keymap.c, ocm/keymap.c, splitbs/keymap.c, and splitrs/keymap.c

- removed duplicate layers from all keymaps and edited per suggestions

- compiled each keymap to check for and correct any potential errors. all compiled with no errors

* Minor Change

- fixed imgur image link in readme.md to be correct format

* Minor Changes

changes to macro layouts in osa.h
changes to dualsplit/keymap.c - added arrows to layer 1

* Changes

- Made changes to info.json to match osa.h
- changes to osa.c enabling indicator LEDs
- changed "dualsplit" directory name to "all" to match keymap naming in osa.h, info.json, and keymap.c
- minor changes to all/keymap.c

* Update keyboards/sck/osa/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Update keyboards/sck/osa/readme.md

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>

* Changes to info.json

- revert to info.json from version in b3b49c3 per requested changes

keyboards/sck/osa/keymaps/splitbs/config.h

@@ -0,0 +1,19 @@
+/* Copyright 2019 jrfhoutx
+ *
+ * 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
+
+// place overrides here