server : refactor (#5882)

server : refactor (#5882)

* server : refactoring (wip)

* server : remove llava/clip objects from build

* server : fix empty prompt handling + all slots idle logic

* server : normalize id vars

* server : code style

* server : simplify model chat template validation

* server : code style

* server : minor

* llama : llama_chat_apply_template support null buf

* server : do not process embedding requests when disabled

* server : reorganize structs and enums + naming fixes

* server : merge oai.hpp in utils.hpp

* server : refactor system prompt update at start

* server : disable cached prompts with self-extend

* server : do not process more than n_batch tokens per iter

* server: tests: embeddings use a real embeddings model (#5908)

* server, tests : bump batch to fit 1 embedding prompt

* server: tests: embeddings fix build type Debug is randomly failing (#5911)

* server: tests: embeddings, use different KV Cache size

* server: tests: embeddings, fixed prompt do not exceed n_batch, increase embedding timeout, reduce number of concurrent embeddings

* server: tests: embeddings, no need to wait for server idle as it can timout

* server: refactor: clean up http code (#5912)

* server : avoid n_available var

ggml-ci

* server: refactor: better http codes

* server : simplify json parsing + add comment about t_last

* server : rename server structs

* server : allow to override FQDN in tests

ggml-ci

* server : add comments

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Co-authored-by: Pierrick Hymbert <redacted>