Add Api Backend wizard causes always error after recent methods changes for settings handling

[jykae]

After previous hotfixing for Settings handling and setup wizard, add API backend wizard causes always error because functions it tries to call were nested under one syncApiBackends server method.

Move functions needed to callable place and get Api Umbrella host from settings.

Check out this: https://github.com/apinf/api-umbrella-dashboard/blob/develop/client/views/api_backends/add/wizard.js#L80