[extension/headersetter] Rename headerssetter to headerssetterextension

[kovrus]

Description:

Rename headerssetter to headerssettersextension and deprecate the github.com/open-telemetry/opentelemetry-collector-contrib/extension/headerssetter module.

Link to tracking Issue:
Resolves #13774

[dmitryax]

I don't think we should strive for maintaining a not breaking developer API in this repo at this point. As long as the configuration interface is not changed (I believe it's still headersetter in the config, right?), I'd recommend just renaming the module.

cc @jpkrohling

[jpkrohling]

I don't think we should strive for maintaining a not breaking developer API in this repo at this point.

That's true, but I also think we should try to have it backward compatible whenever possible, especially to create the right culture for the time we actually need to be backward compatible :-) But if other approvers and maintainers think this should be done in a breaking manner, I'm fine with that as well.

[kovrus]

@open-telemetry/collector-contrib-approvers could someone from approvers and maintainer give their opinion on modules bwc approach?

[bogdandrutu]

Need a rebase

[kovrus]

rebased

[kovrus]

@jpkrohling can you please merge it?