Allow the configuration of an external API that provides campaign data for a campaign.
When a campaign that has been configured to use an external API is sent, Keila should request external data for each contact from that API.
It should provide the following features:
[ ] Define an external API endpoint
[ ] Define API parameters (e.g. contact.email or contact.external_id - see #115)
[ ] Define API authorization (should support Basic Auth and Bearer Token)
Allow the configuration of an external API that provides campaign data for a campaign. When a campaign that has been configured to use an external API is sent, Keila should request external data for each contact from that API.
It should provide the following features:
contact.emailorcontact.external_id- see #115)