feat: new artifacts path and CLI utility (#876)

* fix artifacts path

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

* add docling-models utility

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

* missing formatting

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

* rename utility to docling-tools

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

* rename download methods and deprecation warnings

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

* propagate artifacts path usage for ocr models

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

* move function to utils

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

* remove unused file

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

* update docs

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

* simplify downloading specific model(s)

Signed-off-by: Panos Vagenas <35837085+vagenas@users.noreply.github.com>

* minor refactor

Signed-off-by: Panos Vagenas <35837085+vagenas@users.noreply.github.com>

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Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Signed-off-by: Panos Vagenas <35837085+vagenas@users.noreply.github.com>
Co-authored-by: Panos Vagenas <35837085+vagenas@users.noreply.github.com>