docs: Example on PII obfuscation (#2459)

* added example on PII obfuscation

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

* reformatting code

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

* add in index and fix heading formatting

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

* add GLINER to PII

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

* final commit

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

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Signed-off-by: Peter Staar <taa@zurich.ibm.com>
Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Co-authored-by: Michele Dolfi <dol@zurich.ibm.com>