feat(web, server): Ability to use config file instead of admin UI (#3836)

* implement method to read config file

* getConfig returns config file if present

* return isConfigFile for http requests

* disable elements if config file is used, show message if config file is set, copy existing config to clipboard

* fix allowing partial configuration files

* add new env variable to docs

* fix tests

* minor refactoring, address review

* adapt config type in frontend

* remove unnecessary imports

* move config file reading to system-config repo

* add documentation

* fix code formatting in system settings page

* add validator for config file

* fix formatting in docs

* update generated files

* throw error when trying to update config. e.g. via cli or api

* switch to feature flags for isConfigFile

* refactoring

* refactor: config file

* chore: open api

* feat: always show copy/export buttons

* fix: default flags

* refactor: copy to clipboard

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

mobile/openapi/test/server_features_dto_test.dart

@@ -21,6 +21,11 @@ void main() {
       // TODO
     });
 
+    // bool configFile
+    test('to test the property `configFile`', () async {
+      // TODO
+    });
+
     // bool facialRecognition
     test('to test the property `facialRecognition`', () async {
       // TODO