qt/qml: Update player toolbar QMenu(s) placement

This MR updates the player toolbar placement for the Bookmark and Renderer QMenu(s). They should now appear above their respective buttons. Placing them below was causing visibility issue on certain cases.

Bookmark and Renderer models now inherit from QmlDynamicMenu that updates their placement dynamically when the size of the QMenu(s) changes. This is particularly useful for the renderer QMenu that changes its content when a new device is scanned.