Decoupling target sending logic from what the payload is

[aerosouund]

The code for sending to targets should not expect that the payload is a policy report. instead it should treat it as an arbitrary object and interact with it through a generic interface. this would allow the later expansion of the tool to support sending things other than policy reports.
Ideally, the code can depend on something like type Payload interface. and any data that we want to send with the reporter can implement this interface. The description of this interface is still to be discussed. Some of the starting methods can be

type Payload interface {
  Timestamp() time.Time // returns the time this payload was created in
  Body() map[string]interface{} // returns the payload in json format
}

Some targets already transform the result into a json serializable struct (s3, webhook, gcs, kinesis, elasticsearch), while others (slack, telegram, loki) do destination specific transformations that may not be very straightforward to make generic.

cc: @fjogeleit @JimBugwadia