Rewrite in Kotlin

[v3n3]

Hello, this is just a note to remember that we should rewrite the lib in kotlin when we get the time.

[v3n3]

Updates for the Flowr class:

• Remove the ToolbarHandler and DrawerHandler.
• Rename setRouterScreen, getRouterScreen, removeCurrentRouterScreen to setFlowrScreen, getFlowrScreen and removeCurrentFlowrScreen.
• Remove SetCustomAnimation.
• Remove onNavigationIconClicked.
• Rename isHomeFragment to isRootFragment.
• Remove syncToolbarState.

Updates for the Builder class:

• Remove onClick
• Remove argument from skipBackStack & clearBackStack