Release 1 of RPM for GNU Hello version 2.10

Set RPM release number to 0 during new version development.

Release 1 of RPM for GNU Hello version 2.9

Bump release number and add changelog entry using rpmdev-bumpspec.

Add preamble and manifesto code snippets for modulefile subpackage.
Add variable to avoid injecting subpackage summary into modulefile.

Add modulefile template. Add modulefile directory macro for installation
and manifesto. Inject spec file variables into modulefile template.

Obtain compiler name and version from environment and use macros to
automate preparation, building and installation processes.

Generate spec file from "rpmdev-newspec -m" and set directory structure
in preparation for concurrent installation of multiple versions.

Redefine _prefix following GNU Coding Standards (GCS) documented at
https://www.gnu.org/prep/standards/html_node/Directory-Variables.html.

Additional work is required to get the expected values for _infodir and
_mandir macros on RHEL 6 systems.