ci: Add CI for docs v2

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SUMMARY

To ensure that our docs v2 build successfully every commit I suggest adding initial CI setup.

I can imagine applying some linting rules for documentation eg. validate links, validate referenced images (see #18090), but we need to start somewhere.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TESTING INSTRUCTIONS

You can see on GitHub Actions the results of the associated CI job.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

@geido, could you take a look?

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I am gonna investigate on my side deeply first to avoid noise on Apache Superset CI.