Need to be able to install from a private ppa

[autonomouse]

We'd very much like to use this, but there doesn't seem to be a way to enter credentials. We're currently installing a deb from our private PPA using charmhelpers.fetch.add_source which does support this, but we'd like to start using layers such as this one instead.

[marcoceppi]

I'll add the apt layer, which implements the configuration options for source/keys

[autonomouse]

You, sir, are a star