Reflect the multi-tenancy capabilities of ADOP

[kramos]

ADOP support multi-tenancy i.e. not all users can see all other users' Jenkins jobs and git repos. Hygieia doesn't currently support that i.e. all dashboards are capable of seeing everything the credentials passed to it have.

ADOP: https://github.com/Accenture/adop-docker-compose

[kramos]

The MVP here is that if you want to protect Hygieia to avoid everyone having access to all data, you could just not let anyone other than an Admin user:

1. Sign up
2. Create dashboards
3. Login
4. See the List of dashboards page i.e. all they would be able to see would be direct dashboard links which are obscure enough due to the giant hash e.g.: http://hygieia-ui.111.111.111.111.xip.io//#/dashboard/578515966d46b20009350de7

So it's the case of: 1 hiding the sign up button on the root context page 2 hiding the #/site page unless someone is logged in.