HMS-5923: add support for rhel10

[xbhouse]

Summary

Adds filters and preselected repositories in the template modal to support RHEL10 repos

Testing steps

1. Checkout this backend PR
2. Run make repos-import && go run cmd/external-repos/main.go process-repos to import and snapshot all repos
3. You should see the RHEL10 repos listed in the UI
4. Create a template with RHEL10 repos, this should work the same as with RHEL8 and 9
5. Filtering templates and repos on version 10 and sorting by version should also work as expected
6. EPEL10 should be listed on the Popular Repositories tab and should be able to be introspected / snapshotted

#testwith content-services/content-sources-backend#1085

[jlsherrill]

https://issues.redhat.com/browse/HMS-5923

[rverdile]

Looks good! will revisit when this is ready to merge

[jlsherrill]

/retest