Rework the interface of PersistentTabView

[jb3rndt]

This should make the PersistentTabView more understandable and robust, expecially when using a custom navbar.

ToDo:

• Remove PersistentTabViewBase which was just wrapped by PersistentTabView
• Make the navbar a builder
• Move itemAnimationProperties out of PersistentTabView and pass it to the NavBar directly
• Move navBarDecoration out of PersistentTabView and pass it to the NavBar directly
• backgroundColor changes navbar color -> move into navBarDecoration
• Move neumorphicProperties out of PersistentTabView and pass it to the NavBar directly
• Rework PersistentBottomNavBarItem to directly set the correct values for the colors
• Unify primary color and secondary color scheme
• Migration guide