Just patch diff to poll store

[dartcafe]

Every single configuration change causes a complete round trip by patching all stores based on the reported request return.

Changes:

• Do not reload full poll on config changes
• Backend additionally sends the diff of the poll attributes after changing
• Only patch the diff to the poll store
• Selective reloading of other stores depending on the changed values

Additionally refactored the permission requests

In very big polls there is still a lag between the user action and applying the changes. Further investigation will be done, to determine, if this can be eliminated, too.