rpm: Turn fedora lister into a generic Red Hat based distribution one

As Red Hat based linux distributions share the same type of package repository,
rework the fedora lister into a generic one to list RPM source packages and
their versions from numerous distributions.

For a given distribution, the RPM lister will fetch packages metadata from a
list of release identifiers and a list of software components. Source packages
are then processed and relevant info are extracted to be sent to the RPM loader.
When all releases and components were processed, the lister collected all versions
for each package name and send those info to the scheduler that will create RPM
loading tasks afterwards.

Nevertheless, as there is no generic way to list all releases and components for
a given distribution but also to guess the right URL to retrieve packages metadata
from, those info need to be manually provided to the lister as input parameters.
Some examples of those parameters for various distributions can be found in the
config directory of the lister.

Regarding the produced origin URLs, as there is no way to find valid HTTP ones
for all distributions, the same behavior as with the debian lister is used and
they have the following form: rpm://{instance}/packages/{package_name} where
the instance variable corresponds to the name of the listed distribution such
as Fedora, CentOS, or openSUSE.

Related to swh/meta#5011.