Add Edited Label to Page View

[ilovecherries]

This adds an edited label to the page view so that some immediate important information about the page is readily available via the activity data.

There is controversy about this, particularly there is concern about the amount of information added to the information bar. As this is beyond the scope of the issue that this is originally made for, I am submitting this as a PR to be
built on later since it seems this relies on some design choices being decided first.

This closes #43.

[y-ack]

not comfortable merging this without an available width check, but that's up to @12Me21

[darienreese]

We probably need to have a strict priority on which information is more important then. Whether it's more important to only show the Edited field or it's important to only show the Created field when the width can't fit both fields.