This release adds a bunch of improvements and new features for SQL template matching

Major

larch.search.template_matcher.SQLTemplateMatcher component is added to do template-matching for SQL queries pr
- larch.search.template_matcher.FuzzySQLTemplateMatcher uses fuzzy-search based match
larch now supports additional/optional dependencies
- larch[paper-qa] for paperqa
- larch[extras] for additional requirements like pandas, spacy, etc.
- larch[url-loaders] can be used to have unstructured related dependencies for loading URLs

Minor

switch to pyproject.toml configuration for pip installation
bugfix larch.indexing.DocumentIndexer.as_langchain_retriever(...) pr
relevance scores are added to all the returns of DocumentIndexer.query_top_k(...)
several bugfixes related to MultiRetrieverSearchEngine