💡 Support per-ingress updates via API

[mattfysh]

Describe the feature you'd like Currently a tunnel configuration can only be updated with a single "replace everything" call to

PUT /accounts/{account_id}/cfd_tunnel/{tunnel_id}/configurations

This overwrites all ingress rules, and requires client-side centralized management of ingress rules

However, if you have multiple teams deploying to a k8s cluster, the lack of per-ingress API management means they cannot independently manage their own ingress slice

Describe alternatives you've considered

1. currently using the TunnelBinding kubernetes CRD from https://github.com/adyanth/cloudflare-operator - you deploy a slice of the ingress rules and the k8s operator will combine rules into a single config and restart cloudflared. This works well, but I'm hearing that locally-managed tunnel configs may soon be deprecated in favour of remotely-managed
2. deploying a tunnel per-ingress. This seems like a wasteful use of cluster resources

Additional context N/A

[mattfysh]

cc @jcsf via https://github.com/cloudflare/cloudflare-docs/pull/21116