service output directory

[egandro]

This is a minor goa example enhancement.

--service-output allows the services to be created e.g. in pkg/services

This separates the files e.g. that we create in cmd.

example

goa example --service-output ./pkg/services

[egandro]

I keep this as draft, because I would love to get some thumbs up or down.

I didn't like the service.go files flying at the top of the project

[raphael]

Hello, that makes sense, there are a couple of considerations that come to mind:

1. We've been trying to keep goa as flag-less as possible to keep its usage super simple, tweaks to how the generators work are typically done via the Meta DSL.

2. This is changing the path to the service Go package which has the potential to break other generated code that depend on it (e.g. transport, plugins). So we'd probably need some extensive tests for this that cover not just where the files are generated but also ensure that import statements are properly generated for code that depend on them.