Document GitRepo/HelmOps status fields and conditions

[weyfonk]

This page lacks information about:

• statuses in which a GitRepo (or a HelmOp, for that matter) can find itself
• conditions applicable to either of those resources

Let's fix this, which will help users understand resource statuses, and give the UI team a solid base upon which to build Rancher's new continuous delivery dashboard.

[manno]

This could be extended with information on

• when a status is updated, e.g. when a bundledeployment is updated
• which fields and lists are inherited/aggregated from which other resource

Some of that information is already in our API docs: https://github.com/rancher/fleet/blob/main/pkg/apis/fleet.cattle.io/v1alpha1/status.go#L5
And the tests are also helpful:

• integrationtests/controller/cluster/status_test.go
• integrationtests/controller/clustergroup/status_test.go
• integrationtests/controller/bundledeployment/status_test.go
• integrationtests/controller/bundle/status_test.go
• integrationtests/gitjob/controller/status_test.go
• e2e/single-cluster/status_test.go