Use the combination of path-ordered leaves names and a hash of combined
fingerprint as variant_id. This should improve human-readability of the
results and also it should produce machine-friendly unique names, which
change when values in variant are modified.

Because the leaves names are ordered by path, the order of yaml file
does not affect the variant_id. On the other hand any modified/added
value changes the fingerprint and therefor variant_id.

Important feature is also that the variant still contains the
default_params, but the variant-id is not affected by it.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>