Add SSO support for Jenkins in the service Mojo spec

[Caio Begotti]

The current Mojo spec deployment of Capomastro will not expose its Jenkins unit, but there might exist situations in which it would be interesting to expose Jenkins (for when we need to manually patch the XML config of a project). IS maintains ci.admin.canonical.com with a neat SSO support that we could use. Apparently artifacts exposed to unauthenticated users would not be a problem anymore as the whole site is behind SSO. Also, in case of an archiver failure in Capomastro there is still a way to get artifacts out of the service.

[Daniel Manrique (roadmr)]

Can Capomastro access Jenkins behind SSO, or would it have a way to hit some sort of private address to avoid needing this?

This is a great idea but sounds like a larger feature and may involve mostly charming and spec work. I'll set for future for the time being.