HMS-9959: support extended release versions for templates

[rverdile]

Summary

Adds support for extended release versions to templates

Testing steps

1. Create a template with an extended release version
2. Make sure to set the extended_release_version and extended_release
3. Register the template to system: https://github.com/content-services/content-sources-backend/blob/main/docs/register_client.md
4. refresh subscription manager
5. Set the release version on the system e.g. echo "9.6" | sudo tee /etc/dnf/vars/releasever
6. Try downloading a package e.g. dnf install httpd

[xbhouse]

https://issues.redhat.com/browse/HMS-9959

[dominikvagner]

2 small comments, otherwise it looks great! ✨
tested it with a system and everything works as expected! 🚀

[rverdile]

updated

[dominikvagner]

awesome work! thx! ✨

ack! ✅