Config enhancements

I would like to propose the following config options to be added to this plugin. I would be happy to submit a pr for these enhancements but I was hopping to get some feedback beforehand.

1. Add a config called something like codeArtifactResolversEnabled that defaults to true to continue current behavior. I have a use case where I would just like to use this plugin to publish to CodeArtifact and not pull from it.
2. Add a config called something like codeArtifactErrorOnInvalidConfig that defaults to true to continue current behavior. If this is set to false it will only print out the error as a warning. This will limit how often I need to generate the aws auth token since the jars should live in my local cache.

Let me know what you think! I should have a pr up in the next week or so.

[douglasthomsen]

I have created the following pr to address the second enhancement. I do not need the first one anymore.

#32