This patch is a part of vector_store_client sharded service
implementation for a communication with vector-store service.
It adds a `services/vector_store_client.{cc|hh}` sharded service and a
configuration parameter `vector_store_uri` with a
`http://vector-store.dns.name:port` format. If there will be an error
during parsing that parameter there will be an exception during
construction.
For the future unit testing purposes the patch adds
`vector_store_client_tester` as a way to inject mockup functionality.
This service will be used by the select statements for the Vector search
indexes (see VS-46). For this reason I've added vector_store_client
service in the query processor.
Reference: VS-47 VS-45
7bf53fc908