Feature request: IAM system

[percevalw]

Feature type

After discussing with @scossin, it would be a nice feature to be able to use the IAM system with EDS-NLP. Since this library already ships with a spaCy connector, a first step would be to create a documentation page here referencing the project and demonstrating it on an example similar to the Matcher to inform users.

To make this component compatible with edsnlp, the only things missing are:

• the ability to add the detected entities to the Doc.ents and to assign them a label, either fixed or dynamic according to the kb_id of the retrieved entity
• make it available via spaCy's entry points (spacy_factories)

We could also add the IAM system as a matcher (https://github.com/aphp/edsnlp/tree/master/edsnlp/matchers), but this would require splitting it into multiple parts to remain modular (add spellwise to normalizers, trie + simstring / levenshtein / ..., make it accept a dict of patterns, etc) so let's keep it simple for now.