Be able to enable/disable labs from the RLMS management

[porduna]

Do something like "disable this lab" (for maintenance or whatever) and automatically it will not be available by any School. In OpenSocial, it would be interesting that this was propagated to the widget, showing something like a message or so (e.g., "The lab is down at this moment" or similar). In the RLMS Registered Labs tab, it should be a tick or something in a new column that you can toggle.