improve flexibility of the movie node in shader editor

Add the possibility to connect inputs to the texture movie/image sequence node in the shader editor for the values of -frame, -start frame and -offset.

That would help a lot for randomization (smoke video on planes, very unrealistic if they are all in sync! and having 50 materials just for this is not very efficient).

TBH I am very surprised that there is no input on those, maybe a technical limitation prevents this? also, if the node could successfully read the number of frames the animation is, that would be super helpful as well.