Chaotic directory structure of eventing-contrib

[daisy-ycguo]

Expected Behavior

All event sources are stored in clear directory structure and easy to locate.

Actual Behavior

There are several event sources. Some are in eventing-contrib repo, some are in eventing repo, and some are in both. Even the structure of sources in eventing-contrib repo is chaotic. It's hard for new comers to locate. And new contributors don't know which directory to contribute.

Sources under eventing-contrib are in chaotic structure:

• camel/source
• gcppubsub
• kafka/source
• contrib/awssqs
• contrib/github

Sources under eventing are in good shape structure:

• contrib/gcppubsub
• contrib/kafka
• contrib/natss

gcppubsub and kafka are in both.

Steps to Reproduce the Problem

1. Review the directory structure of eventing-contrib

Additional Info

1. The directory structure of every event source is in good shape. So we just need to restructure eventing-contrib and get a clear structure.
2. Better to clear document which directory an event source contributor shall go to.

[grantr]

/kind cleanup