Edit->View display refactor; Availability attribute

The switch between view and edit is now a property of the container and behaviour of specific elements is determined by their classes.

Availability is a self assigned property that has a status symbol chosen from a few general indicators, and a free text message that can be used to give more details. The availability is always supplied with a lifetime after which it disappears. Can be used broadly from marking long term absences to short periods of unavailability.

Closes #1 (closed) (mostly, integrations with things like HR would be difficult to deal with sensitive information)