Decouple dispatching logic from its process

[a3kov]

Currently dispatcher is a GenServer, and you have to dispatch using GenServer API.
I think it would make sense to move the dispatching logic to a separate module, so that developer could use the dispatcher without spawning a separate process. This would help people use the library on a deeper level if they have custom requirements (e.g. using webhook message sourcing).
People who want to keep on using the dispatcher process would be able to continue doing so.
What do you think ? Does it make sense ?