[PROPOSAL] move DCO check to GitHub setting

[rursprung]

What/Why

What are you proposing?

currently, this repository is using the GH action workflow dco.yml to verify that a sign-off is provided. nowadays, this can be controlled directly via GitHub settings (see the GH documentation). for OpenSearch this has already been changed a year ago by @VachaShah in https://github.com/opensearch-project/OpenSearch/pull/2317

if this is done it should also be documented that the same needs to be done on repositories started off of this template (presuming they want the DCO).

What users have asked for this feature?

n/a

What problems are you trying to solve?

align repositories, use standard features of GitHub.

What is the developer experience going to be?

n/a

Are there any security considerations?

n/a

Are there any breaking changes to the API

n/a

What is the user experience going to be?

n/a

Are there breaking changes to the User Experience?

n/a

Why should it be built? Any reason not to?

n/a

What will it take to execute?

• admin user to set the setting on the GH repo
• PR to remove the DCO workflow

Any remaining open questions?

n/a

[dblock]

We have a DCO bot enabled for the org. The manual DCO check can be deleted.