post https://{server_name}/agent-hub/campaigns
name: < string, required, min: 1, max: 150 >
description: < string, optional, max: 255 >
notes: < string, optional, max: 500 >
is_default: < integer, optional, (0 or 1) >
base_charge: < Double-precision floating-point, required, min: 0, max: 100 >
perc_charge: < Double-precision floating-point, required, min: 0, max: 20 >
accounts: < optional, an array of all submerchant account_ids> (if passed the campaign being created will overwrite the currently applied campaigns of the given merchants)