Pre-cPMig: transfer non-account-related migration files and run cpeval

I tried to keep most of the pre-cpmig code in one section.

Also changed the giturl:
giturl="https://raw.githubusercontent.com/CpanelInc/cPMigration/PUBLIC/c
pmig.sh"

I did not understand exactly how the error_check could be streamlined
and used properly.  Maybe that needs to be addressed. For example, if
you use the pre-cpmig option, it will check for, among other things,
number of IP addresses, and ask questions and possibly 'bail out', even
though you weren't trying to actually transfer files.