Create ci-launch directory on the puppetmaster.

While credentials for clouds are uploaded by hand, the place they are
put is constant and has one correct setting for mode and owner, so
lets automate it.

Change-Id: I98ce4493c260f97c3ac1028d7065536178760d72
Make third-party imports clearer in launch/.

This is a minor step towards PEP-8 as well, but mainly makes it easier
to document what third party modules are needed.

Change-Id: Id901ef437fcdeb11c8dd555e8db7c13daa86c4b2