Renamed HttpClientConfig to HttpRequestConfigBuilder and updated its uses
Additionally, refactored http request configurations construction to be outside of the execution consumer to avoid multiple constructions in case the request is retried.
Removed timeout declarations from request configurations because the http client assigns them automatically.
Issue https://ontotext.atlassian.net/browse/GDB-3503
Additional changes:
- Moved statement methods from the base repo client to the RDF repo client
- Added constant for the namespaces rest path