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

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

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

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

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

...e-llama/templates/components/vectordbs/python/pg/index.py

...e-llama/templates/components/vectordbs/python/pg/utils.py

packages/create-llama/templates/python.ts