Use standard humanized timestamps for moderation

The original intention was to show messages like

	Hidden by Foo after 7 minutes

Unfortunatly this is not currently supported by the cldr extension
and creating new internationalized timestamp rendering is beyond
the MVP scope of the flow project.

Change-Id: Id4b5a106785334f2e427ce91e0ef9b12b78a133a
Merge "Use standard humanized timestamps for moderation"