Plugins: Make open method clearer to use

This highlights that the FileHandler class can also be seen as a method
similar to open, and it removes unnecessary context managers, allowing
plugins to close files as they wish (they must, however, remember to
close the file for it to be committed).

volatility/framework/plugins/__init__.py

@@ -19,7 +19,7 @@ def construct_plugin(context: interfaces.context.ContextInterface,
                      automagics: List[interfaces.automagic.AutomagicInterface],
                      plugin: Type[interfaces.plugins.PluginInterface], base_config_path: str,
                      progress_callback: constants.ProgressCallback,
-                     file_handler: Type[interfaces.plugins.FileHandlerInterface]) -> interfaces.plugins.PluginInterface:
+                     open_method: Type[interfaces.plugins.FileHandlerInterface]) -> interfaces.plugins.PluginInterface:
     """Constructs a plugin object based on the parameters.
 
     Clever magic figures out how to fulfill each requirement that might not be fulfilled
@@ -30,7 +30,7 @@ def construct_plugin(context: interfaces.context.ContextInterface,
         plugin: The plugin to run
         base_config_path: The path within the context's config containing the plugin's configuration
         progress_callback: Callback function to provide feedback for ongoing processes
-        file_handler: Object to pass any generated files to
+        open_method: class to provide context manager for opening the file
 
     Returns:
         The constructed plugin object
@@ -49,6 +49,6 @@ def construct_plugin(context: interfaces.context.ContextInterface,
         raise exceptions.UnsatisfiedException(unsatisfied)
 
     constructed = plugin(context, plugin_config_path, progress_callback = progress_callback)
-    if file_handler:
-        constructed.set_file_handler(file_handler)
+    if open_method:
+        constructed.set_open_method(open_method)
     return constructed