Improve section edit button styling and behavior

1. Fixes the layout of section-edit buttons so that, in the words of Dave Matthews, they're correctly space-betweened
2. Hides the section's edit button when editing
3. Reverse the order of the buttons
4. Bonus: Trim the top/bottom margins from the first/last elements within the section-edit display boxes (so headings start at the top of the box, and paragraphs/etc. stop at the bottom -- without unwanted padded whitespace)
5. Bonus #2: Make some requested text formatting changes.

Closes https://code.librehq.com/ots/clients/lfc/torque-tracker/-/issues/344