Add users by QR code

[TR-SLimey]

Second attempt (#2276) including all fixes from review of last PR.

Fixes #2025

Also fixes a small typo in RoomDirectoryItem.kt

Pull Request Checklist

• Changes have been tested on an Android device or Android emulator with API 21
• UI change has been tested on both light and dark themes
• Pull request is based on the develop branch
• Pull request updates CHANGES.md
• Pull request includes screenshots or videos if containing UI changes
• Pull request includes a sign off

Screenshots

Sharing user by QR code (Light theme)

Sharing user by QR code (Dark theme)

Tested and working:

• Request permissions before opening scanner
• Cleanly close scanner if permissions not granted
• Open scanner if permissions granted (even after denied previously)
• Open DM if it already exists
• Create DM if it does not
• Let user know that they cannot DM themselves if they try
• Show progress while creating DM
• Tell the user if QR code is not valid
• Generate valid QR codes in user profile

Signed-off-by: TR_SLimey | [email protected] | @tr_slimey:an-atom-in.space

[bmarty]

Hello, thanks for the update.
The PR is really great! I have some few remark, and especially one about moving the treatment into the ViewModel. Feel free to ask if you need help, or if you prefer us to do the change.
QR code dialog and QR code scanning tested OK on my device.
Thanks again!

[TR-SLimey]

Hey, @bmarty I noticed this PR is still sitting around, anything I can do to help it along or is it blocked by something?

[BillCarsonFr]

Hello @TR-SLimey , I took your commits and put them here #2417
In a more generic PR to improve invite.
Closing this PR in favor of that one