feat: support pgvector

[Anhui-tqhuang]

add pgvector as one option to vector store with the following configurations

The available configuration options are:

Field	Description
host	The server hosting the Postgres database. Default is localhost
port	The port on which the Postgres database is accessible. Default is 5432
database	The specific database to connect to. Default is postgres
user	The username for database access. Default is postgres
password	The password for database access. (Required)
embed_dim	The dimensionality of the embedding model (Required)
schema_name	The database schema to use. Default is private_gpt
table_name	The database table to use. Default is embeddings

[github-actions]

Published docs preview URL: https://privategpt-preview-f2b40408-318a-4fd5-b971-54bb5b0f5075.docs.buildwithfern.com

[github-actions]

Published docs preview URL: https://privategpt-preview-4bb3e1dc-4c20-4bc6-a35f-4121b150776c.docs.buildwithfern.com

[github-actions]

Published docs preview URL: https://privategpt-preview-5c06aaa5-1adc-4384-8f94-cceac206bc1f.docs.buildwithfern.com

[imartinez]

Great addition and execution!

[github-actions]

Published docs preview URL: https://privategpt-preview-a3d00891-90e5-46b7-943e-1e1cf78a6f16.docs.buildwithfern.com