make sure that crowbar is running

it may not be started when it is installed from git
Make sure that Crowbar is properly installed before continuing
Add new packages (Savanna, oslo.rootwrap)
Add more debugging
crowbar-prep.sh: add --media-mirror option

Since @saschpe sneakily changed the default to match his preferences ;-)
crowbar-prep.sh: move constants to beginning of script
crowbar-prep.sh: parametrize SP3 media NFS export subdirectory name
crowbar-prep.sh: parametrize SP3 ISO name
crowbar-prep.sh: add optional support for HAE ISO
crowbar-prep.sh: assign some variables after option parsing

In particular, variables depending on CLOUD_VERSION should be
set after the CLI arguments are parsed.
crowbar-prep.sh: assign static strings in the same place
crowbar-prep.sh: avoid hardcoding repo name in multiple places
crowbar-prep.sh: remove preexisting any Devel:Cloud:Shared repo
crowbar-prep.sh: Devel:Cloud:Shared only used for SUSE Cloud 3
crowbar-prep.sh: fix ibs_repo bug

Previously only worked if -p was specified before -d or -s, not after.
crowbar-prep.sh: avoid blank line leakage from multiple runs
crowbar-prep.sh: add missing dependency of D:C:3:S on D:C:3

Devel:Cloud:3:Staging only provides a subset of Devel:Cloud:3, so
-s requires adding Devel:Cloud:3 too.