[feat] Support LinodeObjectStorageBucket deletion if forceDeleteBucket is set

[AshleyDumaine]

What this PR does / why we need it:
We want to be able to clean up buckets, which is very useful in the cases of test clusters or short-lived / non-production clusters.

This PR adds the missing bucket deletion functionality which will only perform the bucket deletion (including ALL OBJECTS IN THE BUCKET) if LinodeObjectStorageBucket.spec.forceDeleteBucket is set to true (defaults to false). This is leveraged in the etcd-backup flavors via the FORCE_DELETE_OBJ_BUCKETS env var (defaults to false).

Which issue(s) this PR fixes:
Fixes #415

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• adds or updates e2e tests

Testing

1. Create a cluster that uses the etcd-backup addon like kubeadm-full. Make sure to enable bucket force-deletion:

make local-release # for the updated etcd-backup templates
make local-deploy 
export FORCE_DELETE_OBJ_BUCKETS=true
clusterctl generate cluster test-cluster --kubernetes-version v1.31.8 --flavor kubeadm-full --infrastructure local-linode:v0.0.0 > test-cluster.yaml
# optionally check the test-cluster.yaml
kubectl apply -f test-cluster.yaml

2. Ensure the test-cluster-etcd-backup bucket shows up in your account
3. Delete the cluster:

kubectl delete cluster test-cluster

4. Ensure the test-cluster-etcd-backup bucket disappears from your account

[codecov]

Codecov Report

Attention: Patch coverage is 79.39914% with 48 lines in your changes missing coverage. Please review.

Project coverage is 63.50%. Comparing base (ad49dff) to head (4181923).

Files with missing lines	Patch %	Lines
...controller/linodeobjectstoragebucket_controller.go	47.50%	18 Missing and 3 partials ⚠️
cloud/services/object_storage_buckets.go	75.55%	10 Missing and 1 partial ⚠️
cloud/services/object_storage_objects.go	91.42%	6 Missing and 3 partials ⚠️
cloud/scope/object_storage_bucket.go	83.72%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #780      +/-   ##
==========================================
+ Coverage   62.93%   63.50%   +0.56%     
==========================================
  Files          69       69              
  Lines        6735     6958     +223     
==========================================
+ Hits         4239     4419     +180     
- Misses       2254     2288      +34     
- Partials      242      251       +9     

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[tchinmai7]

patch instead of update?

[AshleyDumaine]

This is following the same logic as https://github.com/linode/cluster-api-provider-linode/blob/main/cloud/scope/common.go#L188-L199 which uses Update but I'm not opposed to using Patch if that works better

[tchinmai7]

just worried about potential conflicts - since this is a different object

[AshleyDumaine]

conflicts are already be handled via retry/requeue on the bucket reconciler but maybe switching to patch would help with that

[tchinmai7]

should we delete page by page? might help avoid cases where the objectsToDelete is too large for a single request

[AshleyDumaine]

This is borrowed from https://github.com/linode/terraform-provider-linode/blob/v3.0.0/linode/helper/objects.go#L173, I think it should be fine for us