Add option --plugin-dirs (#11277)

Closes #3260
Authored by: imranh2, coletdjnz

Co-authored-by: coletdjnz <coletdjnz@protonmail.com>

yt_dlp/plugins.py

@@ -15,6 +15,7 @@ from zipfile import ZipFile
 
 from .compat import functools  # isort: split
 from .utils import (
+    Config,
     get_executable_path,
     get_system_config_dirs,
     get_user_config_dirs,
@@ -84,6 +85,12 @@ class PluginFinder(importlib.abc.MetaPathFinder):
         with contextlib.suppress(ValueError):  # Added when running __main__.py directly
             candidate_locations.remove(Path(__file__).parent)
 
+        # TODO(coletdjnz): remove when plugin globals system is implemented
+        if Config._plugin_dirs:
+            candidate_locations.extend(_get_package_paths(
+                *Config._plugin_dirs,
+                containing_folder=''))
+
         parts = Path(*fullname.split('.'))
         for path in orderedSet(candidate_locations, lazy=True):
             candidate = path / parts