Fix RTL language causes OSC to malfunction, #4878

[low-batt]

This commit will:

• Add initializers to TimeLabelOverflowedStackView, TimeLabelOverflowedView and TouchBarPlaySliderCell that set userInterfaceLayoutDirection to be leftToRight
• Change MainWindowController.windowDidLoad to set the userInterfaceLayoutDirection property of fragControlView and oscFloatingTopView to be leftToRight
• Change constraints from leading/trailing to left/right for several OSC components to prevent them from moving when a RTL language is used
• Change MainWindowController methods mouseDown and mouseDragged to take into account the userInterfaceLayoutDirection setting during playlist resizing
• Change ControlBarView.mouseDragged to take into account the userInterfaceLayoutDirection setting when repositioning the floating OSC
• Rename the play property in the Constants struct to be blackRightPointingTriangle
• Add a blackLeftPointingTriangle property to the Constants struct
• Change PlaylistViewController.tableView to use a right or left arrow based on the userInterfaceLayoutDirection setting
• Change the language-direction of the pip and volume related icons and the playlist icon from Fixed to Left to Right, Mirrors

This adjusts IINA's behavior to match Apple's guidance that video controls and timeline indicators should not flip in a right-to-left language. Other controls, such as the volume control and the pip and playlist buttons are flipped for RTL languages.

This also corrects problems dragging the floating OSC and resizing the playlist when a right to left language is configured.

• I have read CONTRIBUTING.md
• This implements/fixes issue RTL language causes OSC to malfunction  #4878.

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Description:

[low-batt]

Found another problem. Dragging the floating OSC is messed up. Putting this in draft mode until I can fix that.

[uiryuu]

The changes look harmless. If @ShlomoCode agrees to all the changes, then we can merge.

[ShlomoCode]

I've actually been using a local build of these changes for a few weeks now, and it's working great. One thing I feel uncomfortable with is the order of the custom buttons, discussed in this comment and below and was not decided: #4878 (comment)

Another little thing is this icon:

Its direction is determined by the language of the application, but it should be determined by the language of the operating system, because it is the system language that determines the PIP location.
That is, in case the system language is RTL, even if the language defined for the application is LTR, the PIP will open on the left side, and vice versa.

[ShlomoCode]

🤔

[uiryuu]

@ShlomoCode Please try the latest version on enable-he branch and report anything looks incorrect and file an issue.

The custom buttons are on the left now.

As for the PIP button direction problem, please file another issue for that, thank you!