Refactor & document v1's movecopy action to be clearer
Refactor & document v1's movecopy action to be clearer

 * Update v1.provider.movecopy to distinguish between action names
   that are applicable to the auth handler and action names that are
   applicable to the provider.
   - Provider actions are native actions supported by providers:
     "move", "copy"
   - Auth actions are actions used by the auth handler to infer the
     required permissions need to perform the action: "move", "copy",
     or "rename"

  * Replace dict['key'] with dict.get('key', 'foo')

  * Document action usage and scheme in the method doctring.

RCOSDP/waterbutler,TomBaxter/waterbutler,CenterForOpenScience/waterbutler,felliott/waterbutler,rdhyee/waterbutler