Document Versions QA feedback, round 3

[myovchev]

Fixes

• A document with no versions (typically a draft never published before the upgrade) opens the versions modal to its message alone; it no longer shows the document's tabs over an empty body. The tabs appear once a version is shown.
• A first version's change list says "This is the first recorded version. There is no earlier version to compare it with." instead of "No changes recorded for this version.".

Outstanding changes

• i18n: versionFirst replaces versionNoChanges