CORE: Feature selections by admin

[cwang]

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

Right now we have 3 key user features:

• General Chat
• Ask Your Documents
• Ask Shared Documents

Admin should be able to choose which user features are available for use.

Describe the solution you'd like

Part of the system settings.

Describe alternatives you've considered

N/A

Additional context

N/A

[cwang]

Fixed by #27, could you check @janaka and close if fixed pls

[janaka]

@cwang functionally works fine.

FWIW - UX wise not intuitive because the feature flag name and feature name in the UI aren't related enough. It's sufficient for now, especially given there are few options. I'll cut an issue to address in the future.