Update bundled kickstart `repodetect.sh` to support EL10

[silug]

Summary

The simp-core distribution kickstart repo detection script still targets EL7/EL8 only.

Findings

• Script advertises support for versions 7 and 8 only.
• No EL10 branch in distro/version case logic.

Evidence

• simp-core/build/distributions/RedHat/8/x86_64/DVD/ks/repodetect.sh:11
• simp-core/build/distributions/RedHat/8/x86_64/DVD/ks/repodetect.sh:62
• simp-core/build/distributions/RedHat/8/x86_64/DVD/ks/repodetect.sh:86

Impact

EL10 bootstrap/install workflows may not receive repo configuration from kickstart helper logic.

Proposed Fix

Add version-10 handling and corresponding repo definitions.

Definition of Done

EL10 installs using this kickstart helper generate valid repo --name entries and complete successfully.