Feature flags (#543)

* Re-organize a bit controllers

* Added the featureflagcontroller

* Implement feature flags in the front-end

* Clean env files

* Clean console.log messages

* Fix feature flag test

client/composables/useFeatureFlag.js

@@ -0,0 +1,5 @@
+
+export function useFeatureFlag(flagName, defaultValue = null) {
+  const featureStore = useFeatureFlagsStore()
+  return featureStore.getFlag(flagName, defaultValue)
+}