Show server version and active/disabled features

### Is your feature request related to a problem? Please describe.

Specifically, I was trying to use the E2E encryption with the Nextcloud Android app (3.13.1 on Android 11), and I was struggling to find out why this did not work or where it might have been available.

As a customer/user of a hosted solution, I do not have access to the admin panel to check which features are enabled or even easily check which version the server is running from the client, and which major functions may or may not be active that translate to functions in the app not being available.

(I can see which apps are enabled when I log in to the web client under Settings/App Order, but that is a different thing.)

### Describe the solution you'd like

In the client, perhaps in `Settings` or a new adjacent `Server Info` section, it should show which version the client is connected to and those features of the app that are not enabled due to version mismatch or being disabled.

### Describe alternatives you've considered

I checked the web UI as a logged in user, but the information I was looking for was not available there either. (I thought the "About" section might help, but it doesn't have even the version number. Nor in the Settings section.)