Sign bundle manifest excluding certain fields and add the signature as an annotation

[sp1999]

Issue #, if available:
#2855

Description of changes:
This PR adds bundle manifest signing to the EKS-A release CLI to prevent tampering for extended kubernetes version support and also adds the signature as an annotation to the bundle so that it can be fetched by the controller for signature verification.

This PR also fixes all the lint errors in the release folder. Following are the most common lint errors:

1. api/v1alpha1/bundle_types.go:330:6: exported: exported type TinkerbellBundle should have comment or be unexported (revive)
type TinkerbellBundle struct {
     ^

2. api/v1alpha1/release_types.go:85:2: var-naming: struct field BundleManifestUrl should be BundleManifestURL (revive)
        BundleManifestUrl string `json:"bundleManifestUrl"`
        ^

3. api/v1alpha1/bundle_types_test.go:20:2: dot-imports: should not use dot imports (revive)
        . "github.com/onsi/gomega"
        ^

The second and third errors have been ignored by using //nolint:revive comment.

Testing (if applicable):
Ran the following commands from the root folder:

make -C release build
make -C release lint
make -C release unit-test
CGO_ENABLED=0 make -C release dev-release

Verified that the generated bundle manifest has the expected annotations:

apiVersion: anywhere.eks.amazonaws.com/v1alpha1
kind: Bundles
metadata:
  annotations:
    anywhere.eks.amazonaws.com/excludes: 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
    anywhere.eks.amazonaws.com/signature: MEQCIHpe9cu3f6RJJI9PWcPh4ioVl5sXr4sPxUPH/dDESRoWAiBvcL8SAYXxnFqYQ4yYgsXoQc/IJemG1dejaJJOhiwQmg==
  creationTimestamp: "2025-01-12T19:07:26Z"
  name: bundles-0
spec:
  cliMaxVersion: v0.0.0
  cliMinVersion: v0.0.0
  number: 0
  versionsBundles:

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.37%. Comparing base (3711d8f) to head (81410a5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9150   +/-   ##
=======================================
  Coverage   72.37%   72.37%           
=======================================
  Files         585      585           
  Lines       45708    45708           
=======================================
  Hits        33082    33082           
  Misses      10888    10888           
  Partials     1738     1738           

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[sp1999]

/hold
/approve

[eks-distro-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sp1999

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• OWNERS [sp1999]

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[sp1999]

/unhold

[abhay-krishna]

Is this just to make the Go code idiomatic?

[sp1999]

Yes