Magic link auth

[aruss]

TBD;

Generation of links should be done via HTTP API

Example request

{
  "returnUrl": "http://localhost:21402/fancy-campaign",
  "validTil": "2019-04-23T18:25:43.511Z",
  "validateUrl": "http://localhost:21402/check?fancy-compain",
  "lifetime": 1337,
  "userAccounts": [
    "alice@localhost",
    "bob@localhost",
    "bill@localhost"
  ]     
}

Example response

{
  "results": [{
    "email": "alice@localhost",
    "activateUrl": "http://localhost:5000/foo/activate/6970e2e5-3e8a-4da3-a4cf-cc8cb137ab5b",
    "authUrl": "http://localhost:5000/foo/login/f4fe3d17-d524-4efb-809d-02e17e46f158"
  }, {
    "email": "bob@localhost",
    "activateUrl": "http://localhost:5000/foo/activate/f3df273e-0b7f-4cb8-ab7d-2cdff8b02482",
    "authUrl": "http://localhost:5000/foo/login/793f94ac-f6c2-42d7-a880-b1f4005a364c"
  }, {
    "email": "bill@localhost",
    "activateUrl": "http://localhost:5000/foo/activate/e41e570a-5e0c-4759-9e67-4889f9683b8e",
    "authUrl": "http://localhost:5000/foo/login/bcc56959-8e79-41d6-b050-5e9d485b290d"
  }]
}