Is there any program that can add titlebar functionality to the menubar panel?
Most of what you're asking is already there...


The top of every window has Close, Minimise to Dock &amp; Fullscreen buttons.

Alt/click the fullscreen button will maximise instead.
Click &amp; hold the fullscreen button then drag to the left or right of the screen will enable Split Screen.

Additional features can be added to the title bar - right click to Customise
 
You can resize any window except fullscreen by dragging any edge or any corner.

From edges...
Alt/drag will resize from 2 sides.
Shift/drag will resize from 3 sides.
Alt/Shift/drag will resize from all 4 sides.  

From corners...
Alt/drag will resize by mirroring the faces.
Shift/drag will resize from one corner, preserving aspect ratio.
Alt/Shift/drag will resize from all 4 corners, preserving aspect ratio.

Cmd/drag will allow you to resize without bringing the window to the front.
Adding any of the other modifiers will do as above, without bringing it to the front.
Double click to maximise/minimise is an option in System Prefs > Dock