Feat[cl]: Add postgresql vector store for fastapi (#318)

templates/components/vectordbs/python/pg/__init__.py

templates/components/vectordbs/python/pg/constants.py

templates/components/vectordbs/python/pg/context.py

templates/components/vectordbs/python/pg/generate.py

templates/components/vectordbs/python/pg/index.py

templates/components/vectordbs/python/pg/utils.py

templates/python.ts