Backport of Add release notes 1.16 rc into release/1.16.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #17665 to be assessed for backporting due to the inclusion of the label backport/1.16.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
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The person who merged in the original PR is:
@im2nguyen
This person should manually cherry-pick the original PR into a new backport PR,
and close this one when the manual backport PR is merged in.

merge conflict error: POST https://api.github.com/repos/hashicorp/consul/merges: 409 Merge conflict []

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

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Description

Testing & Reproduction steps

Links

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• 755bd95 - 5e74587 - 5732d3b - ea673de - f4ad44b - 822231b - 1e3170c - f7246af - 7ef2df6 - 9fe135b - 7994d05 - c08bf28 - bb5bfba - cf111ab - 777f06f - cfb03bd - 31d3e7c

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1 out of 2 committers have signed the CLA.

• im2nguyen
• temp

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[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR