feat(keymap): Add binding get/set, layer movement

* Add keymap API for getting/setting a bindings
  in keymap layers.
* Add layer move support via intemediary ordering array.
* Add settings storage for keymap changes.

app/Kconfig

@@ -258,6 +258,26 @@ rsource "src/split/Kconfig"
 #Basic Keyboard Setup
 endmenu
 
+menu "Keymaps"
+
+config ZMK_KEYMAP_LAYER_REORDERING
+    bool "Layer Reordering Support"
+
+config ZMK_KEYMAP_SETTINGS_STORAGE
+    bool "Settings Save/Load"
+    depends on SETTINGS
+    depends on ZMK_BEHAVIOR_LOCAL_IDS
+
+if ZMK_KEYMAP_SETTINGS_STORAGE
+
+config ZMK_KEYMAP_LAYER_NAME_MAX_LEN
+    int "Max Layer Name Length"
+    default 20
+
+endif
+
+endmenu # Keymaps
+
 rsource "src/studio/Kconfig"
 
 menu "Display/LED Options"