Add more convenient way to set authorization

[snaggen]

I don't know if there is any support for Basic Auth, couldn't find it in the docs. If not, it would be nice to have. Currently I just set the header Authorization: Basic ... , but I think it would be nice to be able to set the username and password instead.

[LucasPickering]

I like this idea. I think the best design would be adding a new field to the Recipe type called authorization, which has multiple variants. This would override the Authorization header. Some examples:

get_user:
  name: Get User
  method: GET
  url: "{{host}}/anything/{{user_guid}}"
  authorization: !basic
    username: "{{username}}"
    password: "{{password}}"

get_user:
  name: Get User
  method: GET
  url: "{{host}}/anything/{{user_guid}}"
  authorization: !bearer
    token: "{{token}}"