Gallery - context menu - 2nd Attempt

[nayooti]

closes #944
closes #891

Since MessageKit-files were deleted I was not able to rebase properly, so I had to rebase "manually" using this branch.

This PR:

• context menu now displays (and plays) videos like on Telegram.
• context menu works on different device rotations
• context menu closes on device rotation -> this is intended native behaviour
• context menu for documents gallery in iOS 13
• contextMenuProvider to generate legacy and new styled context menus
• context menu provides show in chat that redirects to the message in chat view
• same menu applied to DocumentGalleryController (modern context menu uses default preview)

Gallery did not look nice in landscape on devices with notch. I did a quick fix in this PR too.

To test:

• use videos+images in landscape and portrait
• try device in portrait and landscape

replaces #952

[cyBerta]

I just had a short check on my phone. It looks great, video works too. What is missing is support for gif files. At least the first image of an gif should be shown, if previewing gifs is not possible. Currently there's a white image shown.

[cyBerta]

see my comment

[r10s]

great!

some ui things:

• the delete-button should be red (see other apps)
• once tapped, there should be a confirmation (also see other apps)

to the general understanding:

• the menu is a normal ViewController, or? os maybe call it ContextMenuViewController.swift to point out that it is just this. i was a bit confused what a MenuController is :)
• all in all this is some code and complexity - if we want to get the menu to the document view and - even more interestingly - to the normal chatview, we can resuse ContextMenuViewController.swift? (of course, we would need to add renderings for normal messages and files then)

[nayooti]

MenuController is from Apple to show the old context menu (iOS 12 and lower)
`ContextMenuViewController' to show new context menu (iOS 13 and after).

ContextMenuViewController is embedded into the iOS13-context menu and used to display different viewTypes. It can be easily be reused and extended. For example to be used in ChatViewController, but obviously this needs to be extended for different MessageTypes.

The complexity is only that we have to cover both context-menu-styles as long we support iOS12 and lower.
After all, the complexity isn't too bad IMO.

[nayooti]

@r10s I could not find any suitable confirm-delete-string. Any idea?

[r10s]

we're getting closer :)

some more things, for ios 11, 12:

• when the old-style context menu is opened, a tap outside the context menu should just close it. however, then this tap goes to the image, it also enlarges the image. this enlargement should require a second tap.

you can test this eg. in "iPhone 8 (iOS 12.2)" emulator

things for ios 13+:

• when the new-style context menu is opened, a tap outside the context menu should close it. this is correct. a tap inside, on the preview image should directly enlarge the image. please check the normal ios gallery to get the idea.

• the delete confirmation is okayish, however, the ios gallery stays in the context-menu for the confirmation. this is no blocker, however, if this is easily doable by only setting a flag or so, we should just do it the same way. if it adds complexity, however, we should postpone it.

[nayooti]

@r10s Ok, I am done for now.

[cyBerta]

There's an unresolved merge conflict and unfortunately also new merge conflcts with latest master that need to be resolved, too.

[cyBerta]

lgtm, I fixed the merge conflict and removed the controls from the video preview, because a tap on any item within the preview will open the preview controller, so the controls can never be triggered. It's now the same UI as in the iOS Gallery wrt. video previews.