llama : add reranking support (#9510)

llama : add reranking support (#9510)

* py : add XLMRobertaForSequenceClassification [no ci]

* py : fix scalar-tensor conversion [no ci]

* py : fix position embeddings chop [no ci]

* llama : read new cls tensors [no ci]

* llama : add classigication head (wip) [no ci]

* llama : add "rank" pooling type

ggml-ci

* server : add rerank endpoint

ggml-ci

* llama : aboud ggml_repeat during classification

* rerank : cleanup + comments

* server : accept /rerank endpoint in addition to /v1/rerank [no ci]

* embedding : parse special tokens

* jina : support v1 reranker

* vocab : minor style

ggml-ci

* server : initiate tests for later

ggml-ci

* server : add docs

* llama : add comment [no ci]

* llama : fix uninitialized tensors

* ci : add rerank tests

ggml-ci

* add reranking test

* change test data

* Update examples/server/server.cpp

Co-authored-by: Xuan Son Nguyen <redacted>
* add `--reranking` argument

* update server docs

* llama : fix comment [no ci]

ggml-ci

---------

Co-authored-by: Xuan Son Nguyen <redacted>
Co-authored-by: Xuan Son Nguyen <redacted>