Remove deprecated constructs

[uogbuji]

We have some constructs which have ben deprecated for a few releases now. Target 0.8.0 for removal.

grep -ri "depreca" pylib/*   
pylib/__init__.py:    warnings.warn(DeprecationWarning('Use the openai_api class\'s first_choice_text() method instead'))
pylib/__init__.py:    warnings.warn(DeprecationWarning('Use the openai_chat_api class\'s first_choice_message() method instead'))
pylib/embedding/qdrant.py:# Deprecating the old name
pylib/embedding/qdrant.py:        warnings.warn('qdrant_collection is deprecated. Use collection instead.', DeprecationWarning)
pylib/embedding/pgvector_data_doc.py:            warnings.warn('query_tags is deprecated. Use tags instead.', DeprecationWarning)
pylib/embedding/pgvector_data_doc.py:            warnings.warn('query_tags is deprecated. Use tags instead.', DeprecationWarning)
pylib/llm_wrapper.py:            warnings.warn('api_base is deprecated; use base_url instead', DeprecationWarning, stacklevel=2)

Note: I'm deprecating ogbujipt.embedding.pgvector_message.get_table, renaming to get_chatlog, but we'll target that for 0.9.0 removal.

[uogbuji]

Done