Add a 'Child mode'

**Context**
I want to allow my child communicate (text/audio/video) with his family via Element (on a phone with no SIM and firewall allowing internet access only to Element). I have created for him a dedicated Element account in which I have created DirectMessages conversations with only trusty contacts.
Now I want to be sure he doesn't contact (nor be contacted by) anyone else than those trusty contacts.

**Solution I'd like**
I'd like to find in the Settings a possibility to block features that are unwanted for a child usage: block sending/accepting Invites, block access to Rooms, block addition/removal of Rooms/DirectMessages, block join/quit.
Unlocking this should require to type the account password.
This feature could be called 'Child mode'.

Thanks for reading, and keep up the good work !