GUI: provide for correct link to web doc

Current link in "Help" menu is https://www.bornagainproject.org/m

Presumably, it should lead to https://bornagainproject.org/latest/

The same in some other places

changed milestone to %21 GUI fixes

added GUI release-critical labels

changed title from GUI: provide for correct link to web doc in "Help" menu to GUI: provide for correct link to web doc

changed the description

mentioned in merge request !828 (merged)

mentioned in commit 6684ae50

closed with merge request !828 (merged)