templates/issue: fullscreen redesigned filter view

Create filter view is one of the most used view in CIBugLog, probably the second most used after IndexView. Currently it's big modal that is nearly fullscreen but not really. I would like to change that by redesigning view a little bit so it's fullscreen, header and footer stays in the same place so action buttons like "Check" are easilya available without scrolling. I've also moved "stats" view to the footer so it's also always vissible. Last thing I've changed is a "Loading" spinner that I think is a nice touch.

Demo: link There are some artifacts probably related to video compression.