windowManager: Use one consistent animation mode for minimize/unminimize

Firstly don't use EASE_IN for any minimize/unminimize animations because
those start slow and end fast. The effect of that was minimize/unminimize
appearing to be unresponsive to user clicks for a little while before
accelerating away. All such animations should be EASE_OUT for an immediate
response followed by deceleration at the end.

Secondly we replace the shallow 200ms QUADratic curves with a steeper
400ms EXPOnetial curve. Because it's steeper and twice as long the fast part
feels the same as 200ms QUAD, but there's an extra 200ms after that in which
to slow down smoothly giving a more fluid appearance. No sudden stops.

Fixes: https://bugzilla.gnome.org/show_bug.cgi?id=786789
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2066>
(cherry picked from commit 9069183c)