Add documentation on load_examples with official Docker and helm

[xinbinhuang]

cloeses: #14491

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In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
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[mik-laj]

Can you do a rebase? Documentation for Helm Chart has been moved to the new documentation package. See: #14643

[xinbinhuang]

@mik-laj just rebased to master

[github-actions]

The Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks,^Build docs$,^Spell check docs$,^Backport packages$,^Provider packages,^Checks: Helm tests$,^Test OpenAPI*.

[kaxil]

Build docs step is failing @xinbinhuang

[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest master or amend the last commit of the PR, and push it with --force-with-lease.

[xinbinhuang]

@kaxil Fixed! Tested locally.