feat: add peering config to mesh CRD

[DanStough]

Changes proposed in this PR:

• Adding a new field to the mesh CRD that will be used to turn on routing of peering control-plane traffic through a mesh gateway(s). Consul PR link

How I've tested this PR:

• I've just been running unit tests. Right now nothing in Consul is listening to this flag - more integration testing required at that point. Also assuming that the changelog will be deferred until that point (please correct me if this isn't convention).

How I expect reviewers to test this PR:

• Hopefully CI tests are sufficient.

Checklist:

• [X] Tests added
• [ ] CHANGELOG entry added (TBD)

  HashiCorp engineers only, community PRs should not add a changelog entry. Entries should use present tense (e.g. Add support for...)

[DanStough]

@thisisnotashwin this will be for 1.14. I guess a few weeks before the release is a good time to merge?

[thisisnotashwin]

@thisisnotashwin this will be for 1.14. I guess a few weeks before the release is a good time to merge?

Yup!! that sounds perfect!! Thanks Dan!

[david-yu]

@DanStough Should this go out for 1.14 beta? If so, I think this needs a re-base off of main

[DanStough]

@david-yu . Nope, not required for the beta. I will rebase shortly though.

[DanStough]

@ndhanushkodi would you be available to review? I finally rebased everything so there shouldn't be conflicts.

[ndhanushkodi]

Will wait for peering acceptance tests to pass then merge