Add accounts to shortcuts (and additional sidebar view for large screens)

**Is your feature request related to a problem? Please describe.**
As many people refuse Telegram usage, they awaiting similar handy target reading of Fediverse accounts instead of mixing they in general timeline. For now to read folowed account we must to search it, then open profile, then activate "+Replies" option. It is too much taps for simple action.

**Describe the solution you'd like**
I propose:
1. Add option to add accounts as shrotcuts (with additional options to show replies/boosts/media, and if possible to specify source instance - my or this account's own)
2. Extend maximum count of shortcuts (over 9).
2.a. For small screens add scroll into shortcuts popup
2.b. For large screens add compact vertical left-sided sidebar with only avatars of shortcutted accounts (or any other combinations of solution you see) with nickname highlight on hover