feature/copy-vault-dataloader: Add method get_real_file(file_path) to dataloader

- get_real_file will decrypt vault encrypted files and return a path to
  a temporary file.

- cleanup_real_file will remove a temporary file created previously with
  get_real_file

lib/ansible/plugins/action/copy.py

@@ -152,6 +152,8 @@ class ActionModule(ActionBase):
         diffs = []
         for source_full, source_rel in source_files:
 
+            source_full = self._loader.get_real_file(source_full)
+
             # Generate a hash of the local file.
             local_checksum = checksum(source_full)
 
@@ -219,6 +221,8 @@ class ActionModule(ActionBase):
                 # We have copied the file remotely and no longer require our content_tempfile
                 self._remove_tempfile_if_content_defined(content, content_tempfile)
 
+                self._loader.cleanup_real_file(source_full)
+
                 # fix file permissions when the copy is done as a different user
                 self._fixup_perms(tmp, remote_user, recursive=True)
 
@@ -247,6 +251,8 @@ class ActionModule(ActionBase):
                 # the file module in case we want to change attributes
                 self._remove_tempfile_if_content_defined(content, content_tempfile)
 
+                self._loader.cleanup_real_file(source_full)
+
                 if raw:
                     # Continue to next iteration if raw is defined.
                     self._remove_tmp_path(tmp)