docs: DPK pipeline example using docling library (#2112)

* Notebook showing example on how to use docling transforms in DPK

Signed-off-by: Maroun Touma <touma@us.ibm.com>

* fix HF Token name

Signed-off-by: Maroun Touma <touma@us.ibm.com>

* use %pip instead of pip install jupyter lab

Signed-off-by: Maroun Touma <touma@us.ibm.com>

* run formatter

Signed-off-by: Maroun Touma <touma@us.ibm.com>

* add example to mkdocs and fix typo

Signed-off-by: Maroun Touma <touma@us.ibm.com>

---------

Signed-off-by: Maroun Touma <touma@us.ibm.com>