Implement support for KEDA in Radix

[emirgens]

Get some insight from the community on which scalers(features) can be the most important. Implement on scaler first and then scale up in the next iteration.

Update radix-config / radix-operator
Install KEDA in infrastructure

User requests:

• https://github.com/equinor/radix/issues/63
• https://github.com/equinor/radix/issues/54

Involve users: Inge, Ronnie, John Ivar

Keda discussion on Workload Identity:
kedacore/keda#5630 (comment)

TODO:

• Add KEDA to Dev cluster radix-flux#2078
• Install KEDA in all clusters radix-flux#2081
• Get HPA by Label selector radix-api#625
  • Release API
• Create scaling objects instead of hpa radix-operator#1116
  • Tag and Release Operator
• Custom scaling triggers radix-operator#1112
• Update operator with keda support radix-api#629
• Upgrade horizontal scaling information (Keda) radix-api#633
  • Return all triggers, current metric, target metric, errors (invalid spec/missing auth etc)
• Show keda scaling status radix-web-console#1040
  • Show trigger/scaling status
  • Show more relevant information when scaled to 0
• Add Keda documentation, fixed highlighting of yaml and dockerfile radix-public-site#356
• enable keda metrics radix-flux#2152
• Announce

---

• Upgrade CRD to allow secrets for auth
• Upgrade Radix API to set secrets
• Upgrade Radix CLI to set secrets
• Write documentation

Triggers:

• https://keda.sh/docs/2.14/scalers/azure-service-bus/
• https://keda.sh/docs/2.14/scalers/cron/
• https://keda.sh/docs/2.14/scalers/cpu/
• https://keda.sh/docs/2.14/scalers/memory/

DoD
A scaler can be configured and the applicable Pods are scaled using the rules. Information provided in web-console: which scaler, status etc.