Refactor type generator

* Allows for generating top-level types for any embedded struct so
  that sub-types can be properly instantiated from calling code
  * Specifying `-no-embedded-types` will generate top-level types
    rather than embedding the struct

* Refactored "Device" API
  * All fields set to `omitempty` because it describes all possible
    device types, so effectively any field could be omitted any time
  * Fixed `get` call for "Device" API; replacing `rest` with `stat`

* Generated `get` and `update` calls for `Setting*` APIs

* Added `5.14.23` JSON files

fields/5.14.23/SettingMgmt.json

@@ -0,0 +1,20 @@
+{
+  "alert_enabled": "true|false",
+  "auto_upgrade": "true|false",
+  "boot_sound": "true|false",
+  "led_enabled": "true|false",
+  "advanced_feature_enabled": "true|false",
+  "outdoor_mode_enabled": "true|false",
+  "unifi_idp_enabled": "true|false",
+  "x_mgmt_key": "[0-9a-f]{32}",
+  "x_ssh_keys": [
+    ""
+  ],
+  "x_ssh_username": "^[_A-Za-z0-9][-_.A-Za-z0-9]{0,29}$",
+  "x_ssh_password": ".{1,128}",
+  "x_ssh_md5passwd": "",
+  "x_ssh_sha512passwd": "",
+  "x_ssh_enabled": "true|false",
+  "x_ssh_bind_wildcard": "true|false",
+  "x_ssh_auth_password_enabled": "true|false"
+}