Possibility to change the ApiGateway name

[a-marcel]

This is a Feature Proposal

Description

Currently, the generation of the api gateway name is static and not match our naming.

https://github.com/horike37/serverless-step-functions/blob/6415b356f321dd7e34e51b97e85b0817a6a9fce6/lib/naming.js#L53

For feature proposals:
It is possible to set the name via configuration ?

Thanks