Remove deprecated AUTH_PASSWORD setting

[danhermann]

Removes the auth.password setting for monitoring HTTP exporters. Users must switch to the secure auth.secure_password setting.

Relates to #50919

Docs preview: http://elasticsearch_54892.docs-preview.app.elstc.co/diff

[elasticmachine]

Pinging @elastic/es-docs (>docs)

[elasticmachine]

Pinging @elastic/es-core-features (:Core/Features/Monitoring)

[danhermann]

@elasticmachine run elasticsearch-ci/docs

[lcawl]

I think the auth.password needs to be removed from the example in https://www.elastic.co/guide/en/elasticsearch/reference/master/http-exporter.html too.

[danhermann]

I think the auth.password needs to be removed from the example in https://www.elastic.co/guide/en/elasticsearch/reference/master/http-exporter.html too.

Thanks for catching that, @lcawl. I'll update that example.

[danhermann]

@elasticmachine update branch

[danhermann]

@elasticmachine run elasticsearch-ci/2

[lcawl]

Documentation changes LGTM, thanks!

[danhermann]

@elasticmachine update branch

[jakelandis]

LGTM