Add basic functionality to timelines

[alexmodrono]

Changes Overview
This PR makes the following changes:

• Now you can do infinite scrolling on timelines to see older posts.
• Now you can pull to refresh to get the latest posts.

While this pr was mostly focused on improving timelines, it also:

• Improved attachments:
  • Introduced Galeries: attachments are now shown in galleries that allow you to see them in a fancier way.

    • NOTE: Galleries show up to 3 attachments max.

• Improved the status view.
• Simplified ProfileView.
• Introduced more bugs we'll need to fix later.

Does this PR fix, close, or implement any issues?

• [x] This PR closes, fixes, or implements the following issues.

• Implements #8
• Somehow contributes to #6

Known issues

• If you tap below the author's profile view, the app will crash. As far as I know, it is caused because the Avatar's nav link is triggered at the same time as the other thread nav link, so UIKit crashes because there are "multiple active destinations". Fixed by 29d1749b43fe389e39a91e9273c2189edba28050
• You still can't view attachments in full screen.
• If you go to a profile that isn't yours, the banner and the avatar won't load.

Pending for review
@hyperspacedev/swift-ui

[alexmodrono]

The profile page appears to be fine, but I am running into this fatal error when tapping on a post from the Network tab:

2020-08-23 21:32:39.929392-0400 Hyperspace[830:147862] WF: _WebFilterIsActive returning: NO
2020-08-23 21:32:40.117865-0400 Hyperspace[830:147862] [assertion] Error acquiring assertion: <Error Domain=RBSAssertionErrorDomain Code=2 "Specified target process does not exist" UserInfo={NSLocalizedFailureReason=Specified target process does not exist}>
2020-08-23 21:32:40.117994-0400 Hyperspace[830:147862] [ProcessSuspension] 0x11decfa80 - ProcessAssertion: Failed to acquire RBS Background assertion 'WebProcess Background Assertion' for process with PID 837, error: Error Domain=RBSAssertionErrorDomain Code=2 "Specified target process does not exist" UserInfo={NSLocalizedFailureReason=Specified target process does not exist}
2020-08-23 21:32:40.119401-0400 Hyperspace[830:147862] [assertion] Error acquiring assertion: <Error Domain=RBSAssertionErrorDomain Code=2 "Specified target process does not exist" UserInfo={NSLocalizedFailureReason=Specified target process does not exist}>
2020-08-23 21:32:40.119549-0400 Hyperspace[830:147862] [ProcessSuspension] 0x11decfac0 - ProcessAssertion: Failed to acquire RBS Suspended assertion 'WebProcess Suspended Assertion' for process with PID 837, error: Error Domain=RBSAssertionErrorDomain Code=2 "Specified target process does not exist" UserInfo={NSLocalizedFailureReason=Specified target process does not exist}
Fatal error: UIKitNavigationBridge: multiple active destinations: file SwiftUI, line 0
2020-08-23 21:32:40.292135-0400 Hyperspace[830:147862] Fatal error: UIKitNavigationBridge: multiple active destinations: file SwiftUI, line 0

I am running the latest iOS/macOS betas with the latest Xcode.

Gotcha! Fixed by 29d1749b43fe389e39a91e9273c2189edba28050 :D

Instead of having multiple NavigationLinks, what I did was to reuse one, but with different destinations depending on the activation place, so now the two NavigationLinks don't get triggered at the same time.

[alexmodrono]

Alright so I'm merging this into data/client then.