Improve management of boards and users

[iangray001]

Currently management covers two main configuration points, the available boards and the expected users. These are both detailed in vlab.conf.

Users are handled by creating key pairs in the keys directory on the relay server, and by editing the vlab.conf file. There is no enforcement that these two actually correspond to each other.

Equally, boards are described in vlab.conf and their allowed users, but few checks applied.

All of this could be configured from a better interface (i.e. a web interface) that updates things atomically and consistently.

Equally, adding and removing users requires the entire relay to be reset. This is not a huge problem but could be improved.