[Feature request]: fine-tune a parser

[sylvainkahane]

Is there already a feature request for this?

• I have searched the existing issues

Describe the problem to be solved

With the new interface, we can select a parser, but it is unclear that we can choose it to fine-tune it.
Moreover, some generic parser should be propose: a parser pretrained-all-SUD2.13, pretrained-all-UD2.13, pretrained-all-mSUD2.13

Suggest a solution

Add something like "Fine-tune an existing parser" and put in front the pretrained parsers on all UD and SUD