Revisit default bundle config

[dstandish]

Currently we have a dags_folder entry by default in dag_bundles. I think it's a bit confusing.

When i see that, i assume it's the new location for the old dags_folder setting. or that it's a setting that applies to all dag bundles.

I think we can do something to disabiguate this.

One option would be to do something like this

[dag_bundles]

bundle_configs = [
	{"name": "blah", "classpath": "blah"},
	{"name": "git", "classpath": "somethingsomething.Git","kwargs": {}}
  ]

[Prab-27]

@dstandish , I'd like to work on this issue. Could you please tell me the file path? I'm still new, and I can't find it