handwired/terminus_mini: refactor, Configurator support, and readme cleanup (#5292)

* handwired/terminus_mini: refactor

- white space changes in terminus_mini.h (alignment)
- keymap now uses #include QMK_KEYBOARD_H
- refactored TMK macros into QMK process_record_user
- refactored TMK layer functions into QMK keycodes
- removed redundant keycode definitions

* handwired/terminus_mini: Configurator support

* handwired/terminus_mini: readme cleanup

- completed keyboard description
- removed Hardware Availability line (it was blank)
- updated Docs links

keyboards/handwired/terminus_mini/info.json

@@ -0,0 +1,59 @@
+{
+  "keyboard_name": "handwired/terminus_mini",
+  "url": "",
+  "maintainer": "qmk",
+  "width": 12,
+  "height": 4,
+  "layouts": {
+    "LAYOUT": {
+      "layout": [
+        {"label":"Tab", "x":0, "y":0},
+        {"label":"Q", "x":1, "y":0},
+        {"label":"W", "x":2, "y":0},
+        {"label":"E", "x":3, "y":0},
+        {"label":"R", "x":4, "y":0},
+        {"label":"T", "x":5, "y":0},
+        {"label":"Y", "x":6, "y":0},
+        {"label":"U", "x":7, "y":0},
+        {"label":"I", "x":8, "y":0},
+        {"label":"O", "x":9, "y":0},
+        {"label":"P", "x":10, "y":0},
+        {"label":"Del", "x":11, "y":0},
+        {"label":"Backspace", "x":0, "y":1},
+        {"label":"A", "x":1, "y":1},
+        {"label":"S", "x":2, "y":1},
+        {"label":"D", "x":3, "y":1},
+        {"label":"F", "x":4, "y":1},
+        {"label":"G", "x":5, "y":1},
+        {"label":"H", "x":6, "y":1},
+        {"label":"J", "x":7, "y":1},
+        {"label":"K", "x":8, "y":1},
+        {"label":"L", "x":9, "y":1},
+        {"label":";", "x":10, "y":1},
+        {"label":"'", "x":11, "y":1},
+        {"label":"Left Shift / (", "x":0, "y":2},
+        {"label":"Z", "x":1, "y":2},
+        {"label":"X", "x":2, "y":2},
+        {"label":"C", "x":3, "y":2},
+        {"label":"V", "x":4, "y":2},
+        {"label":"B", "x":5, "y":2},
+        {"label":"N", "x":6, "y":2},
+        {"label":"M", "x":7, "y":2},
+        {"label":",", "x":8, "y":2},
+        {"label":".", "x":9, "y":2},
+        {"label":"/", "x":10, "y":2},
+        {"label":"Right Shift / )", "x":11, "y":2},
+        {"label":"LCtrl", "x":0, "y":3},
+        {"label":"GUI", "x":1, "y":3},
+        {"label":"Lower", "x":2, "y":3},
+        {"label":"LAlt", "x":3, "y":3},
+        {"label":"Space / Lower", "x":4, "y":3, "w":2},
+        {"label":"Enter / Raise", "x":6, "y":3, "w":2},
+        {"label":"MO(_FUNCTION)", "x":8, "y":3},
+        {"label":"MO(_MOUSE)", "x":9, "y":3},
+        {"label":"App", "x":10, "y":3},
+        {"label":"RCtrl", "x":11, "y":3}
+      ]
+    }
+  }
+}