Add a-ball handwired trackball based on ADSN9800 (#9015)

* Initial commit of kball

* Pretty much working

* Rename to aball

* Cleanup

* Fix typo and make instructions

* Refactor to use qmk spi

* Suggestions from ZVECR

* Update keyboards/handwired/aball/adns9800_srom_A6.h

* Update keyboards/handwired/aball/adns.c

* Update keyboards/handwired/aball/adns.c

* Update keyboards/handwired/aball/adns.c

* Added copyright and source attribution

* Update keyboards/handwired/aball/rules.mk

Include as quantum lib to help avoid timing issues with LTO

* Only send report on change, adj sensitivity, fix src include

* Fix issue causing constant reports and bad clamping

* Streamline conversion to int, add required wait before burst read

* Changes to track develop

* Update rules with new feature descriptors, add info.json

* Add stub layout

* Rework / cleanup key matrix.  Add missing CS pin define for new ADNS driver

* Add stub keymap to enable compile

keyboards/handwired/aball/keymaps/default/keymap.c

@@ -0,0 +1,18 @@
+/* Copyright 2020 Richard Sutherland
+ *
+ * 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/>.
+ */
+#include QMK_KEYBOARD_H
+
+