Change display URL format to single string

[RoiEXLab]

Currently the server expects this sort of config:

email: {
    display: {
      server: {
        protocol: 'http',
        host: 'localhost',
        port: 7654,
        baseurl: '',
      },
    },
},

It would be much better, if simply

email: {
    display: {
      server: 'http://localhost/'
    },
},

could be used instead, all we do is append the path anyways