docs: Jobkit and connectors (#2357)

* feat: create documentation for docling-jobkit

Signed-off-by: Lucas Morin <lucas.morin222@gmail.com>

* small text fixes

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

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Signed-off-by: Lucas Morin <lucas.morin222@gmail.com>
Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Co-authored-by: Michele Dolfi <dol@zurich.ibm.com>