Resolve "Add "drawer" overlay on top of PDF viewer"

Closes #410 (closed) (add sidebar)

Closes #426 (closed) (duplicate popup for delete answer)

Closes #427 (closed) (evaluation tags not updating)

Uses bootstrap-vue's sidebar component, currently set to use 75% of viewport width when expanded.

• Added animation on page load (2 bounces)
• Added animation on hover (slight move to left)
• Remove "experimental PDF annotation" banner; we've been using it for 1yr+, I think it shouldn't be experimental anymore
• Drawer shows when looking at a review
• Drawer does not show when looking at a review from an evaluation, instead the questions/answers are shown directly below the PDF