move the log file viewer to its own plugin

We plan to have multiple different types of tabs.

raven/pluginregistry.py

@@ -1,5 +1,5 @@
 from types import ModuleType
-from typing import Dict
+from typing import Dict, Optional
 from inspect import isclass
 from pkgutil import iter_modules
 from pathlib import Path
@@ -46,11 +46,11 @@ class PluginRegistry():
         return PluginRegistry.modules.copy()
 
     @staticmethod
-    def executeSingle(function_name: str, *args):
+    def execute_single(function_name: str, *args) -> Optional[any]:
         return PluginRegistry._execute(function_name, True, *args)
 
     @staticmethod
-    def execute(function_name: str, *args) -> []:
+    def execute(function_name: str, *args) -> [any]:
         return PluginRegistry._execute(function_name, False, *args)
 
     @staticmethod