config: Wrap MatchNameComponent, reduce lock duration

- Remove duplication by merging two MatchNameComponent into a wrapper
- Reduce lock duration by getting list of names under lock and then
  matching names without the lock
- Also, ExpandNodeName's docstring is fixed.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>