CORS-3841: Add custom Endpoints to CAPG

[barbacbd]

What type of PR is this?

/kind api-change
/kind feature

What this PR does / why we need it:

1. Update the api and configs
2. Update the clients to use the endpoints for each service if/when they are supplied
   via the Cluster Spec
3. Allow users to override the GCP Service endpoints for installs that do not allow or want public GCP Service Endpoints.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes # #1391

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• [ x ] squashed commits
• [ x ] includes documentation
• adds unit tests

Release note:

The addition of the ServiceEndpoints in the Cluster Spec allows users to specify custom endpoints for GCP services. This allows users to override their end points for installs that may not allow a public endpoint connection to GCP services.

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @barbacbd. Thanks for your PR.

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[salasberryfin]

Thanks @barbacbd

/ok-to-test

[salasberryfin]

Overall LGTM (pending CI checks). Can you also add this to the book https://cluster-api-gcp.sigs.k8s.io/? Source files can be found here https://github.com/kubernetes-sigs/cluster-api-provider-gcp/tree/main/docs/book

[damdo]

Thanks @barbacbd for contributing this, reads well and makes sense.

/lgtm

[damdo]

@salasberryfin I don't see any docs on similar fields in the book, or am I missing something?

[damdo]

/assign @cpanato @richardcase
for approval

[salasberryfin]

Yes @damdo, you're right. Maybe we can create a separate issue to improve docs on relevant fields in the spec, like what's added here. The book is still lacking lot's of information.

[damdo]

I agree, we probably should, thanks for bringing that up @salasberryfin let's track this separately 👍