Determine UI orientation without shared UIApplication object

[FabioTacke]

This resolves #534.
Using UIApplication.shared makes ChattoAdditions unable to be used in App Extensions. I might not be the only one wanting to use this chat library in an iOS App Notification Service Extension for displaying and storing chat messages that arrived via remote notification.

I replaced the orientation determination with a quite popular method that is totally fine if UIApplication.shared is not an option.

[codecov-io]

Codecov Report

Merging #637 into master will decrease coverage by 0.03%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #637      +/-   ##
==========================================
- Coverage   61.25%   61.22%   -0.04%     
==========================================
  Files          92       93       +1     
  Lines        4969     4972       +3     
==========================================
  Hits         3044     3044              
- Misses       1925     1928       +3

Impacted Files	Coverage Δ
...Additions/Source/Input/ChatInputBarPresenter.swift	60.63% <0%> (ø)	⬆️
...oAdditions/Source/Input/InterfaceOrientation.swift	0% <0%> (ø)

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