Remove excessive network calls from the redhat importer

[TG1999]

Currently we make network calls for reference data in the redhat importer which makes redhat import process slow, we should move these network calls later in an improver which can deal with more type of entities and not only advisories.

[TG1999]

Changes from this PR should be used #1162 when considering improver for this process.

[TG1999]

Use this commit as reference 0a8f7a8 for making improver

[TG1999]

closed by #1162