HMS-5923: add support for rhel10

[xbhouse]

(keeping this in draft until we can use the non-beta repos, but it is ready for a review)

Summary

• Adds support for RHEL10 beta repos
• Adds a new manifest that includes these repos

Testing steps

1. Start with a fresh environment to import the new manifest (make compose-clean make compose-up)
2. Run make repos-import && go run cmd/external-repos/main.go process-repos. All repos including RHEL10 beta should be introspected and snapshotted successfully
3. List the RH repos via API and you should see RHEL10 beta repos in the response
4. Sorting (/repositories/?sort_by=distribution_versions:desc&origin=red_hat) and filtering (/repositories/?origin=red_hat&version=10) these repos by version should still work as expected
5. You should be able to create a template with RHEL10 beta repos, assign it to a RHEL10 beta client (following these docs), and install packages on the client from those repos

[jlsherrill]

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

[rverdile]

Tested repositories list with filtering, snapshots list, templates list, and the various content unit searches. Also made a rhel 10 beta system and was able to install rpms from the template.

Looks good! will revisit when this is ready to merge