Creates a campaign for the authenticated account and returns it in the same UUID-only shape as get_campaign (HTTP 201). campaign_type must be one of the supported type keys (see the enum). eds_uuid (the sending domain / email delivery system) and footer_uuid are required and must reference resources owned by the account -- they become the campaign's defaults and propagate to emails added to its sequences. List the available delivery systems via GET /rest/eds/get_eds and footers via GET /rest/footers/get_footers. After creating the campaign, add sequences to it with create_sequence.