fs: deps/outs: get rid of types (#6054)

Pre-requisite for removing fs.path_info and switching to regular strings
as paths in filesystems.

With new filesystems we no longer need the zoo of different dependency
and output types, as most of them are now just handled by the underlying
filesystem. Though deps/outs are still due for a refactor in other
aspects.

tests/func/test_commit.py

@@ -4,7 +4,7 @@ import pytest
 
 from dvc.dependency.base import DependencyDoesNotExistError
 from dvc.dvcfile import PIPELINE_FILE
-from dvc.output.base import OutputDoesNotExistError
+from dvc.output import OutputDoesNotExistError
 from dvc.stage.exceptions import StageCommitError
 from dvc.utils.serialize import dump_yaml, load_yaml