We need to enhance mach repackage to support building Firefox for Linux RPM packages.

These functions come from the deb repackaging sub-module and were altered to
allow multiple repackaging system.

The test_rpm is mostly based on the test_deb file.

The prefix DEB_ was fully removed from the template variables.

The tests which are already tested in test_utils were removed from test_debian.

The tool rpmbuild come from with the --target parameter which allow to build a
package for a particular architecture (if the building tools are available).

Since the repackage-rpm command do not build anything, this argument can be
used to register the correct information in the generated package.

The --target argument will also add automaticaly the architecture related
entries in the specification file.

This command will generate a RPM package containing a .xpi file which can be
used after that in the dedicated firefox build package.

The langpacks subpackages will be built together with the main packages. To
achieve this behavior, the firefox.spec file is now generated from a jinja2
template instead of the basic template from the string module.

https://hg.mozilla.org/mozilla-central/rev/b7fd45513dbf
https://hg.mozilla.org/mozilla-central/rev/b69571cb9c19
https://hg.mozilla.org/mozilla-central/rev/a5ca243d45aa
https://hg.mozilla.org/mozilla-central/rev/001bb9bd22ab
https://hg.mozilla.org/mozilla-central/rev/2d837ca56796
https://hg.mozilla.org/mozilla-central/rev/474e8391c685
https://hg.mozilla.org/mozilla-central/rev/d0042028b71c
https://hg.mozilla.org/mozilla-central/rev/72394d88dd28
https://hg.mozilla.org/mozilla-central/rev/b23d8196b602