Add a max_crl_size parameter to CRL config

[sgmiller]

Description

If set or the default 100k, CRL building will fail if there are more than
that many entries in the CRL. It will also warn when within 10% of the
limit.

TODO only if you're a HashiCorp employee

• Backport Labels: If this PR is in the ENT repo and needs to be backported, backport
  to N, N-1, and N-2, using the backport/ent/x.x.x+ent labels. If this PR is in the CE repo, you should only backport to N, using the backport/x.x.x label, not the enterprise labels.
  • 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.
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• RFC: If this change has an associated RFC, please link it in the description.
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[github-actions]

CI Results:
All Go tests succeeded! ✅

[github-actions]

Build Results:
All builds succeeded! ✅

[victorr]

LGTM, I have left a suggestion.

Not approving right away to check whether there are docs that need to be updated.

[stevendpclark]

Small nits, nothing preventing merging after api-docs are updated.

[stevendpclark]

Looks great, just need to update the api-docs with the new field name.

[stevendpclark]

LGTM 👍