Instead of repeating the smae string all over the place, let's
have a single constant defined and then used.

If the `--new-profile-id` isn't provided by the user, we will
create the ID of the customized profile ID by appending the
`_customized` suffix to the base profile ID.

This change makes the behavior according to the help text of the
`--new-profile-id` option:
> If left out, the new ID will be obtained by appending '_customized'
> to the tailored profile ID.

and fix the failed asserts

We will move the condition that determines the ID of the customized
profile into the `Tailoring` class. This move helps encapsulate
code and also allows easier unit testing of this feature which
we immediately use to write a unit test in this commit as well :)

This patch adds two new command line options `--rule-role` and
`--rule-severity` that will allow users to refine rule role and
rule seveirty in their customized profile. Using these options
will generate `refine-rule` elements within the output tailoring
file.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2058168

This patch moves the logic for assigning the XCCDF Values for
outer space inside the Tailoring class by defining a method.

Explicitly setting namespaces of elements is the recommended way of using
namespaces. It helps prevent namespace errors. Also, it simplifies unit
testing of code that works with XML elements.

The new name of the variable better describes its actual contents.

This commit adds an integration test for autotailor. The goal
of the test is to verify if the tailoring produced by autotailor
can be loaded and consumed by oscap and if the generated tailoring
leads to the intended behavior of the profile evaluation.

The result will be that the autotailor unit tests will be executed
during the CTest which is run in our CI.