Migrate Rxjava to coroutines #2

[sowjanyakch]

Resolve #4411

• Use only one API for setting password of a room.

🚧 TODO

• ...

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔖 Capability is checked or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

[github-actions]

Codacy

Lint

Type	master	PR
Warnings	94	153
Errors	132	88

SpotBugs

Category	Base	New
Bad practice	6	6
Correctness	16	16
Dodgy code	74	74
Internationalization	3	3
Malicious code vulnerability	3	3
Performance	5	5
Security	1	1
Total	108	108

Lint increased!

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/4446-talk.apk



To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud Talk app.

[sowjanyakch]

The earlier implementation of AlertDialog for weak password does not work as expected. Fixing AlertDialog is out of scope of this PR. This PR only focuses on migrating to coroutines from Rxjava.