CLOUDP-330323: Update atlas core library

[blva]

Proposed changes

Jira ticket: CLOUDP-330323

• Updates the K8s plugin with the latest changes in atlas core library. We made some changes to extend the auth to Service Accounts, as a result that means we need to update the atlas core library with some code breaking changes, hence this PR updating how we use the library to accomodate for that.
• We'll release the CLI, which will migrate users to the new library. Then if a customer try to use the plugin, we'll ask them to update to a newer version of the plugin for full parity.
• The test failure seems unrelated, would be good to get feedback from k8s team about that one

Checklist

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works
• I have added any necessary documentation in the document requirements section listed in CONTRIBUTING.md (if appropriate)
• I have addressed the @mongodb/docs-cloud-team comments (if appropriate)
• I have run make fmt and formatted my code

Further comments

[cveticm]

LGTM!

[cveticm]

Sorry for delayed request, only remembered now: can we remove transport.go and another other unused files?

[cveticm]

LGTM! 🚀

[josvazg]

LGTM