Add auth header support.

[dmeulen]

This makes it possible to authenticate with the gitlab or github API by specifying a PRIVATE-TOKEN or Authorization header with the http request.

Now you can download the ansible source tarball and md5 directly from the gitlab or github package registry using the gitlab API.

example config:

{
  "http-url": "gitlab.ops.catdevbrain.lan/api/v4/projects/4/jobs/artifacts/main/raw/catdevbrain-ansible-latest.tar.gz?job=build_latest",
  "http-checksum-url": "gitlab.ops.catdevbrain.lan/api/v4/projects/4/jobs/artifacts/main/raw/catdevbrain-ansible-latest.tar.gz.md5?job=build_latest",
  "http-proto": "https",
  "http-header-name": "PRIVATE-TOKEN",
  "http-header-value": "<REDACTED>",
  "ansible-dir": "ansible",
  "ansible-inventory": ["inventories/catdevbrain"],
  "playbook": "site.yml",
  "sleep": "10",
  "sleep-jitter": "5"
}

[dmeulen]

Will update whein I find some time, rather busy atm! Thanks for the review!