Export Config: Separate H1 into two distinct fields

[adamfranco]

Currently the H1 (and H2) has a single entry field with a delimiter for the two pieces of data, the full title and the table-of-contents (TOC) title:

This means that formatting instructions are necessary and the Group shows the full string, both adding to visual clutter in the UI.

• [x] Separate the data into two text fields, full title first and TOC text second.
• [x] Drop the formatting instructions
• [x] Title field can have placeholder text like "Full title for section heading".
• [x] TOC text can have placeholder text like "Short title for table-of-contents".
• [x] Change the group title to use only the TOC text, not the full title, for easier scanning of the full config.
• [x] Above changes for H2 as well.

[cg923]

This was my original intention. I ran into issues that were making this take longer than seemed reasonable at the time, but I'd be happy to re-tool it toward this more integrated approach now that other, more important features have been dealt with.

[cg923]

Reopening as group renaming has a bug.