misc fixes

- convert import_source to a decorator which
  wraps the function call in a try block
- fix protocol class when not TYPE_CHECKING
- add id properties to Protocols, remove attributes
  since protocol expects them to be settable but
  NT is read-only
- use id to merge comments
- remove type: ignore's from reddit config
  and just store as 'Any'

my/reddit/pushshift.py

@@ -23,7 +23,6 @@ config = make_config(pushshift_config)
 from my.core import get_files
 from typing import Sequence, Iterator
 from pathlib import Path
-from .common import Comment
 
 from pushshift_comment_export.dal import read_file, PComment