Support HTTP header(s) in HTTP searches

[clarenceb]

The HTTP search type is fairly basic in that it supports GETing an endpoint to check if a site/service is available.

I'd like to be able to pass a HTTP header in the request. Specially, I am trying to hit the "healthcheck" endpoint of my services but they require a "app key" to be passed in as a header. If I could set this header in the HTTP search then I could successfully perform the health checks from 411.

I understand this might not be a generally useful enhancement so I'm putting this here for discussion to gauge interest. I'm happy to contribute a PR if people are interested in this.

[quintanilhar]

Hey @kiwiz, what do you think about this? I supposed that it makes total sense for HTTP API's that requires some type of header authentication.

[kiwiz]

I'd accept a PR for this, but I don't have time to work on it.