move all sidebars to one side for improved UX; add button in head of projects/issues and milestones instead of tab on side of screen to prevent overlapping of content
Merge branch 'responsive-sidebar' into 'master'

Responsive sidebar fixes

This fixes two major issues with the responsive sidebar

1. Overlapping content by the label:
The label and sidebar is now always on the right side of the screen. This makes it always easy to find (better UX) and prevents it from overlapping most content. Additionally, on xs screens, instead of the side-attached label, for some pages it will show an extra button in the head instead of a buttons that overlaps.

2. Pop up of sidebar on changing pages.