feat: add embedding and dynamic model support to Together inference adapter

- updated to use OpenAIMixin
 - workarounds for Together api quirks
 - recordings for together suite when subdirs=inference,pattern=openai

test with:

`TOGETHER_API_KEY=_NONE_ ./scripts/integration-tests.sh --stack-config server:ci-tests --setup together --subdirs inference --pattern openai`

tests/integration/inference/test_openai_completion.py

@@ -96,6 +96,7 @@ def skip_if_doesnt_support_n(client_with_models, model_id):
         #  Error code: 400 - [{'error': {'code': 400, 'message': 'Unable to submit request because candidateCount must be 1 but
         #  the entered value was 2. Update the candidateCount value and try again.', 'status': 'INVALID_ARGUMENT'}
         "remote::tgi",  # TGI ignores n param silently
+        "remote::together",  # `n` > 1 is not supported when streaming tokens. Please disable `stream`
     ):
         pytest.skip(f"Model {model_id} hosted by {provider.provider_type} doesn't support n param.")