Support BasicAuth [wip]

To use BasicAuth either a global auth user or a per hook basis can be
configured.

ToDo:
- Add logic to check if a hook BasicAuth is configured, if not check
  for globaly

Cargo.toml

@@ -28,6 +28,7 @@ ipnet = { version = "2.3", features = ["serde"] }
 thiserror = "1.0"
 run_script = "0.9"
 clap = "3.0.0-beta.5"
+base64 = "0.13"
 
 [package.metadata.deb]
 extended-description = "Webhookey receives requests in form of a so called Webhook as for example sent by Gitea. Those requests are matched against configured filters, if a filter matches, values from the header and the body can be passed to scripts as parameters which are then executed subsequently."