Implement policies for clients

[Flole998]

Over at the Android app, I had the idea to implement policies that allow certain features of the app to be disabled and/or restricted. However, that would require server support and therefor I am also creating a feature request here. It would be perfectly fine to add it to the capabilities and just have it as an option in the config file as this targets more advanced users anyway.

For the complete feature request check nextcloud/android#664

[jasonbayton]

#3456

Related, as MDM plays well into this and can likely be implemented in such a way either the MDM admin or the NC admin can force the client to conform.

[szaimen]

I am going to close this since there doesn't seem to be a lot of interest (no upvotes) and no respond since around 2 years. Please reopen if you still want to implement this.