Add Avatar editor to new conversation dialog

[Antreesy]

☑️ Resolves

• Adds avatar and description editors on conversation create dialog
• Change styles and elements position for avatar editor
• Change "profile picture" to "conversation picture"
• Minor refactoring and fixes

🖼️ Screenshots

🏚️ Before	🏡 After

🚧 Tasks

• Visual check
• Code review

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not required
• 📘 API documentation in docs/ has been updated or is not required
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required
• 🔖 Capability is added or not needed

[nickvergessen]

I love it!

[Antreesy]

@ShGKme FYI: https://github.com/eddyerburgh/jest-transform-stub

Jest doesn't apply transforms to node_modules by default. I guess, the same rules are for jest-transform-stub
I've restored a deleted line in moduleNameMapper

[jancborchardt]

Very nice! :)

Might be good to give the 2 toggles a header too, like "Privacy" or "Conversation visibility". Cause currently they are very close under the picture. But not a blocker.

[Antreesy]

Add a label for toggles. Input was moved to save some vertical space:

Private	Public