GPU Support for Fractal Design Define 7 / Meshify 2

This is an adaptable GPU holder for Fractal Design Define 7 and Meshify 2 cases.
It screws onto the removable front PSU shroud. It can be adjusted side-to-side and also in height.
Remix of borde34's thing:5965813
Can be combined with an improved PSU shroud
(https://www.thingiverse.com/thing:6787262)
to also allow for front-backwards movement. Needs M3 meltable inserts.
Two stems included for different height range

Work in progress, try at your own risk