Raise a warning if multiple plugins exist with same name

[anders-kiaer]

Since we are a plugin framework, there might be plugin projects creating plugins with the same name.

Raise a warning during runtime to give attention to name conflict. This could be done in

webviz-config/webviz_config/plugins/__init__.py

Lines 37 to 39 in 623ab6f

	for entry_point in entry_points().get("webviz_config_plugins", []):
	globals()[entry_point.name] = entry_point.load()
	__all__.append(entry_point.name)

by simply checking if a plugin with name is already in __all__.

The warning should probably include package name of both plugins in order to make it easy for the user to understand where they come from (one way of getting package name from the plugin reference is to use inspect from std.lib).