lib: Reduce diff vs upstream devstack

Revert our local changes for components not currently run nor tested on a
FreeBSD host. There's little sense in providing changes for untested / unused
components.
lib: Wrap host 'install'

This way we can adjust arguments per OS flavor (GNU install has different
arguments than BSD install).
functions: Use sed arguments based on host OS flavor

GNU sed has different arguments than BSD sed.
functions: Use mktemp arguments based on host OS flavor

This accounts for differences between GNU and BSD versions.