BottomTabBarController: Fix the navigation on iPadOS + adjust constraints

This merge request brings a fix to the tab bar on iPadOS with:

• The addition of a BottomTabBarController class that overrides the UITabBarController one and displays the previous tab bar layout at the bottom of the screen.
• The edit tool bar's bottom constraint that is now aligned to the safe area in order to avoid any visual glitch and remove the Xcode generated warning forcing the change.
• The margins and bottom constraint of the current view controller that are adjusted in order to properly be able to fix the mini player if needed.

These changes only apply to iPads running with iPadOS 18.0 and versions above it.

iPad Screenshots

visionOS Screenshots (iPad emulation)

Closes #1873