Favorites feature nav section

[tonygentilcore]

From @aza on October 14, 2016 20:54

• Long hold any channel or identity
• There's a chat action to favorite it
• Tapping causes it to appear in the "favs" section of your home channel's side space/nav

Increases discoverability of channels. Could also be called "pinned" or "star".

Additional feature:

• Long hold any piece of media
• Select "favorite"
• It gets rechat to a @name/favs channel, which also appears in the "favs" section. (might need a better name)

Abilities required:

• Create new chat actions
• Add new section to channel side nav space

cc @tonygentilcore @kharmabum

Copied from original issue: other-xyz/time-cone#128

[kharmabum]

Renaming this issue to help distinguish it from #148