Add more sanitization levels

Some more ideas for sanitization began in #75

Splitting into new issue since original has become basis for #167

### Level 1

Fix the session IDs and subject IDs according to the following rules:

- Any non-alphanumeric -> `+`

Also, write a new column to the requisite tables; `nwb_session_ids` and `nwb_subject_ids`, to record provenance and allow mapping to alleviate confusion.

No modification will be made in-place to the NWB contents.

Required for the majority of Dandisets.

If no possible changes are detected, act as if level 0 (even if level 1 is specified).

### Level 2

Same as level 1 as far as content, BUT edit all NWB file fields in-place accordingly so that they entirely match (are consistent with) the BIDS counterparts

### Level 3+

What other fields are worthy of sanitization?

Start by reading the sanitization ideas in issue #75 and the work that became issue #167. Clarify the required Level 1 behavior for session and subject IDs, including the nwb_session_ids and nwb_subject_ids tables, then determine the scope of in-place Level 2 edits. Level 3+ remains open-ended, so completion criteria need to be agreed before implementation.

Written by the indexing model from the issue text.