Add post interaction accessibility supports and new shortcut for accounts switch

[MainasuK]

Add accessibility supports for:

• Enumerate post components and read the labels
• Supports read and focus on the mentions/hashtags/links in the post content
• Toggle Content Warning and Media Sensitive (Mastodon only)
• Select poll options and submit vote (Mastodon only)
• Trigger post actions like reply, like, e.t.c

Others:

• Long press on the navigation avatar to trigger accounts list scene display

Fixes:

• The boost button may not correctly set to disabled state issue