Fix image zoom / pan / scroll / swipe (#3894)

Migrate to touchimageview from photoview, and adjust the touch logic to correctly handle single finger drag, two finger pinch/stretch, flings, taps, and swipes.

As before, the features are:

- Single tap, show/hide controls and media description
- Double tap, zoom in/out
- Single finger drag up/down, scale/translate image, dismiss if scrolled too far
- Single finger drag left/right
  - When not zoomed, swipe to next image if multiple images present
- When zoomed, scroll to edge of image, then to next image if multiple images present
- Two finger pinch/zoom, zoom in/out on the image

Behaviour differences to previous code

1. Bug fix: The image can't get "stuck" when zoomed, and impossible to scroll
2. Bug fix: Pinching is not mis-interpreted as a fling, closing the image
3. Bug fix: The zoom state of images is not lost or misinterpreted when the user swipes through multiple images
4. Bug fix: Double-tap zooms all the way, instead of stopping
5. Tapping outside the image does not dismiss it, controls and description show/hide

Fixes https://github.com/tuskyapp/Tusky/issues/3562, https://github.com/tuskyapp/Tusky/issues/2297

app/src/main/java/com/keylesspalace/tusky/components/compose/dialog/CaptionDialog.kt

@@ -51,7 +51,7 @@ class CaptionDialog : DialogFragment() {
 
         input = binding.imageDescriptionText
         val imageView = binding.imageDescriptionView
-        imageView.maximumScale = 6f
+        imageView.maxZoom = 6f
 
         input.hint = resources.getQuantityString(
             R.plurals.hint_describe_for_visually_impaired,