Post UI updates (Profile Preview on mobile) (#990)

* Update postmeta to put the timestamp on the right side on mobile

* Drop the two-line PostMeta mode

* Add ProfilePreview modal

* Tune PostMeta to give the best behavior possible for a given platform

* Remove old showFollowBtn attributes

* Fix style issue

* Switch the follow button in the profile header to use the inverted color for consistency with the rest of the app

* Fix lint

* Fix darkmode

* Tune the profile preview footer

* Better analytics choice

src/state/models/ui/shell.ts

@@ -31,6 +31,11 @@ export interface EditProfileModal {
   onUpdate?: () => void
 }
 
+export interface ProfilePreviewModal {
+  name: 'profile-preview'
+  did: string
+}
+
 export interface ServerInputModal {
   name: 'server-input'
   initialService: string
@@ -128,6 +133,7 @@ export type Modal =
   | ChangeHandleModal
   | DeleteAccountModal
   | EditProfileModal
+  | ProfilePreviewModal
 
   // Curation
   | ContentFilteringSettingsModal