Add more elaborate time interval schema's and/or tools

[vmenger]

Currently, the context algorithm detects concepts as historical, current or future. Some more elaborate ways to assign date intervals could be incorporated, as some work has already been done in this domain.

See e.g.:
https://github.com/tuur/AbsClinTimelinesTASL/tree/main
https://aclanthology.org/Q14-1012/
https://www.sciencedirect.com/science/article/pii/S1532046413001032