Feature/excerpt converter form refactoring

Created by: ghost

Just for review. This is a very cumbersome mission, to be able to simplify the entire thing, one would to refactor some other parts as well - tried to get it just to match the old behavior as close as possible.

Ran test with RUN_E2E=true ./tests.sh: all green.

Reviewed by:

• @das-g

Part of #20 (closed) Closes #236 (closed) (by accident)