Add explanation how to add drivers to .YAML

[FionnD]

Feature request

As per this community request here, Max had to explain to a community member how to add a driver to their YAML file. We don't explain this in our documents.

To fix this, I suggest we add

• A subsection to this page with how to add a driver to a YAML.
• In point five of this page, add a reference to the above subsection, and that you should add the jina.resources/executors.requests.CompoundIndexer.yml and remove the !ExcludeQL as Max explains.