Create RPM building containers for both C6 and C7

Move Docker configuration to docker/ subdirectory
Use vagrant as the RPM build user in CentOS 7
Fix chef version in VM to 11.16.4
Improve package name parsing

Raise an error when name is not parseable
Introduce OS version override parameter
Improve pushpkg and rx_pkg

Use the improved OS version checking in pushpkg
Don’t upload an RPM if OS version unknown
Allow override of OS version from command line option

Use CPOD_URL to override the default 'http://cpod.local'
Adapt dante spec file to build on CentOS 7

Incomplete - doesn’t install a systemd service,
just the old init-style.
Fix c-pod::socks recipe, now working on C7

Creates a systemd service, which should be in RPM
Defines ubuntu and debian config files which are
really version dependent, not distribution.

Define configuration variables
Begin upgrade of recipe c-pod::docker

May be best to do a binary install of prebuilt
versions, rather than mess with back-level pkgs

Very Incomplete!