feat: Ability to watch for events in all data centers

[vijayraghav-io]

Description

fixes #20871

Testing & Reproduction steps

Links

PR Checklist

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

[vijayraghav-io]

Sample output with -alldatacenters=true (new flag added)

[vijayraghav-io]

Hi @david-yu / @jkirschner-hashicorp / @huikang, Kindly take this PR for review.

FYI @jakubgs

[vijayraghav-io]

Hi @david-yu / @jkirschner-hashicorp / @huikang , kindly take this PR for approval.

[github-actions[bot]]

This pull request has been automatically flagged for inactivity because it has not been acted upon in the last 60 days. It will be closed if no new activity occurs in the next 30 days. Please feel free to re-open to resurrect the change if you feel this has happened by mistake. Thank you for your contributions.

[vijayraghav-io]

reminding to review/approve this PR