httptest.newRequest is suppose to be used for testing request handing, http.newRequest is for preparing outgoing requests, this allows to fix cache key selection and increase test coverage
Fixes#190.
With this feature unsee can be configured to proxy requests to selected Alertmanager instances, if it's enabled unsee silence form will send a request via unsee rather than directly. This allows users to manage silences in environments where they have access to unsee but not to Alertmanager. Only silences endpoints on Alertmanager API are proxied.