[build & packaging] Reworked the install and packaging so it results in the same
  installation whatever the build is (manual, deb pkg or rpm pkg)
- Use Makefile to make install for deb and rpm as well including config files.
- Include specfile in the dist-gzip so a rpmbuild -tb (tarbuild) can be used
- Added customization for rpmbuild using --with tags (see spec file for
  usage and more details).
- Use adequate default values for rpm. The apache_user is not www-data. it's apache...
- Use /etc/ganglia-webfrontend to store conf.php what ever the distro is.
  Make sure that a link is set to apache config dir using triggers or postinstall.
- Use /etc/ganglia-webfrontend to store conf.php what ever the distro is.
  Use a generic conf.php in /usr/share/ganglia-webfrontend to load the file from
  /etc/ganglia-webfrontend.
- Replaced vargwebstatedir with vargwebdir in conf_default.php.in and Makefile.
- filters dir was not created under debian pkg or manual make install
- Added possibility to have a httpd_group different from user. For instance you
  can choose to install files under apache.daemon identity. If not specified,
  a group with the same name as the user is used.
- Added comment in the install section of the Makefile so it's clear.
- Reworked dist-gzip target so version.php  and spec file are generated while other
  .in files remain so they can be tuned by make or make install.
- Make sure that sharedstatedir is not owned by rpm package (conflict on fc-18+),
  and updated %file section accordingly.
- Removed the manual install and specific config files in debian packaging. Using
  standard make install DESTDIR=...