Update README.md for in-repo pkgscript rationale
Update README.md for in-repo pkgscript rationale

See https://github.com/agrover/configshell-fb/pull/8 comments for more.

Signed-off-by: Andy Grover <b7d524d2f5cc5aebadb6b92b08d3ab26911cde33@redhat.com>

cvubrugier/configshell-fb,agrover/configshell-fb