Description graphs don't have a language anymore

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
For subsumption it is sufficient if the languages have the same base

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Removed multimethod `most-specific-concept'

Making it that generic seems overkill

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Interpretation don't have a language anymore

only concept- and role-names

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>