Decide about attachment preview size

1. Right now it is opened not in full screen.

Proposal 1:

1. Show centered/small window and on image download, we recieve size and if it fit do nothing.
2. If image are bigger, resize panel to full width.

Proposal 2:

Just remember if user opened it to max size, we should do same on next time.

_{View in Huly UBERF-6207}