Can't guarantee this is the final state, but opnsense-bootstrap
stopping over lingering repository information without the finger-
prints in place is not very helpful either.
Now we have a working copy of the file we need, it is already
reconfigured after install and it now also reverts FreeBSD.conf
back to its required state--which is off--to prevent problems.
Now that we have a plist it's easier to review/preview changes.
Can finally tackle the src/opnsense/contrib mess in a sensible
way with this and since we do not rely on mount/umount anymore.
When we build packages, we want to know if something is wrong.
For now, only use it in the upgrade path, not sure how to
to distinguish if a user or the build system is running the
package build.
o Makes live-mounting easier as the package config samples won't
be clobbered anymore.
o Automatically picks up ".in" files, runs replace and moves them
to their permanent location.
o Refactored src directory install while at it.
