docs(flags): add first stage of documentation

docs/README.md

@@ -7,6 +7,10 @@ Developer documentation for the Camunda Modeler.
 
 This shows how to setup and contribute pre-defined custom elements to the modeler
 
+### [Flags](./flags)
+
+This show how to use flags to toggle several features
+
 ### [Plugins](./plugins)
 
 This shows how to use plug into the modeler

docs/flags/README.md

@@ -0,0 +1,39 @@
+# Flags :flags:
+
+Flags allow to disable several features inside the application.
+
+## Available flags
+
+Following flags are available:
+
+- `disable-plugins`: Disabling use of plugins
+- `disable-adjust-origin`: Disabling automatic adjustments to origin coordinates
+- `disable-cmmn`: Disabling `CMMN-Editor`
+- `disable-dmn`: Disabling `DMN-Editor`
+
+All flags are _not_ set per default.
+
+## Use a configuration file
+
+One way to use flags persistently is to create a `flags.json` configuration file inside your user directory. Just modify the configuration file inside your local `{APP_DIRECTORY}/resources` or `{USER_DATA_DIRECTORY}/resources`  location. 
+
+### BPMN-only mode example
+
+One example of using the flags is the BPMN-only mode. To disable the `CMMN-` and `DMN-Editor`, simply modify the `flags.json` configuration file with
+
+```js
+{
+    "disable-cmmn": true,
+    "disable-dmn": true
+}
+```
+
+![BPMN only mode](./bpmn-only.png)
+
+## Use the CLI
+
+Another way to enable feature toggles is simply using them while starting the application via command line on Windows and Linux. E.g. in the case of disabling the `DMN-Editor`, add the following argument to the start command:
+
+```sh
+$ camunda-modeler --disable-dmn
+```