feat(api): add ExternalHost property for routes (backport #877)

[mergify]

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---

Fixes: #726

Description of the change:

• Adds spec.networkOptions.coreConfig.externalHost to the Cryostat v1beta2 CRD.
• Route spec.host is immutable once created. I had considered some logic to recreate the route if the user attempts to change the host in the CR, but this is further complicated due to OpenShift modifying the spec.host field in the default case where it dynamically assigns a hostname. I think trying to accommodate this is too risky for 3.0.

Motivation for the change:

• Allows users to specify a custom hostname for the Cryostat route on OpenShift

How to manually test:

1. Create a Cryostat CR with spec.networkOptions.coreConfig.externalHost defined to a custom value.

---

This is an automatic backport of pull request #877 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 2fc2faa has failed:

On branch mergify/bp/cryostat-v3.0/pr-877
Your branch is up to date with 'origin/cryostat-v3.0'.

You are currently cherry-picking commit 2fc2faa.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   api/v1beta2/cryostat_types.go
	modified:   api/v1beta2/zz_generated.deepcopy.go
	modified:   bundle/manifests/operator.cryostat.io_cryostats.yaml
	modified:   config/crd/bases/operator.cryostat.io_cryostats.yaml
	modified:   config/manifests/bases/cryostat-operator.clusterserviceversion.yaml
	modified:   internal/controllers/reconciler_test.go
	modified:   internal/controllers/routes.go
	modified:   internal/test/resources.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   bundle/manifests/cryostat-operator.clusterserviceversion.yaml

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[ebaron]

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