Show a link to the MAAS server.

When the provider is MAAS, display a link
to the MAAS management interface in the
header.

Also implemented the EnvironmentGet call
in sandbox mode.
Merge pull request #620 from frankban/maas-server-link

Show a link to the MAAS server.

When the provider is MAAS, display a link
to the MAAS management interface in the
header.

Also implemented the EnvironmentGet call
in sandbox mode.