docs: clarify feature flags config

README.md

@@ -16,3 +16,23 @@ The individual modules like "Reporting" require some setup and environment varia
 
 - **[Reporting](./docs/modules/reporting.md)**: Calculate aggregated reports and run queries on all data, accessible for external services for API integrations of systems
 - **[Export](./docs/modules/export.md)**: Template based file export API. Uses [carbone.io](https://carbone.io) as templating engine.
+
+_Modules have to be enabled via a feature flag in the environment config and may need additional environment variables (see module READMEs)._
+
+
+-----
+# Development
+
+## Configuration through environment variables
+Environment variables can be defined in an .env file using "snake case" variable names (see [examples/application.env](/docs/examples/application.env)).
+These are transformed automatically to be available in the code as nested properties
+
+For example, `FEATURES_EXPORTAPI_ENABLED=true` in .env can toggle the feature flag
+```
+@ConditionalOnProperty(
+    prefix = "features.export-api",
+    name = ["enabled"],
+    havingValue = "true",
+    matchIfMissing = false
+)
+```

docs/modules/export.md

@@ -21,6 +21,16 @@ REST controller responsible for handling export operations related to templates.
 [export-api-v1.yaml](../api-specs/export-api-v1.yaml)
 
 ## Setup
+This module has to be enabled through a feature flag in the environment:
+
+in .env file:
+`FEATURES_EXPORTAPI_ENABLED=true`
+or as .yml:
+```
+features:
+  export-api:
+    enabled: true
+```
 
 Configure a compatible render api in the environment. You can use the default, aam-internal implementation,
 but make sure, that the authentication is configured: