Backport of VAULT-32206: verify audit log and systemd journal secret integrity into release/1.18.x

[hc-github-team-secure-vault-core]

Backport

This PR is auto-generated from #28932 to be assessed for backporting due to the inclusion of the label backport/1.18.x.

The below text is copied from the body of the original PR.

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Description

In our effort to ensure that no unhashed secret values are ever present in Vault unauthenticated output streams, we now utilize Vault Radars scanning capabilities to look for both known and unknown secret values in both the Vault audit log and it's service log, the systemd journal. We utilize Radar's kvv2 index scanning feature to scan for known kvv2 secret values in addition to things that look like sensitive credentials.

As part of out integration we also move away from using Github secrets in the enterprise context and instead utilize values in the hosted vault instances.

This has been tested against versions listed in VAULT-30557 and properly detects token values.

TODO: We'll need to remove those as possible initial version targets, or perhaps skip the verification step using a semver constaint.

TODO only if you're a HashiCorp employee

• Backport Labels: If this fix needs to be backported, use the appropriate backport/ label that matches the desired release branch. Note that in the CE repo, the latest release branch will look like backport/x.x.x, but older release branches will be backport/ent/x.x.x+ent.
  • LTS: If this fixes a critical security vulnerability or severity 1 bug, it will also need to be backported to the current LTS versions of Vault. To ensure this, use all available enterprise labels.
• ENT Breakage: If this PR either 1) removes a public function OR 2) changes the signature
  of a public function, even if that change is in a CE file, double check that
  applying the patch for this PR to the ENT repo and running tests doesn't
  break any tests. Sometimes ENT only tests rely on public functions in CE
  files.
• Jira: If this change has an associated Jira, it's referenced either
  in the PR description, commit message, or branch name.
• RFC: If this change has an associated RFC, please link it in the description.
• ENT PR: If this change has an associated ENT PR, please link it in the
  description. Also, make sure the changelog is in this PR, not in your ENT PR.

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Overview of commits

• 3b31b3e

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CI Results:
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