Radrecord

Adds the following fields:
- Hospital Affiliation (`hospital_affiliation`, a multi-line free-text field)
- Informed Consent (ICATH) Provider (`is_icath`, a flag)
- WPATH Provider (`is_wpath`, a flag)
- ADA/Wheelchair Accessible (`wheelchair_accessible`, a flag)
- Sliding Scale (`sliding_scale`, a flag)

The new flag fields (as well as the existing `visible` field) are now coerced appropriately with a `convert_boolean` method.

We now have a single `normalize_record` method that normalizes categories/populations and performs coercion of all boolean fields.

All normalization and validation functions are now backed by a suite of unit tests in `rad_record_tests.py`.

Addresses cases when `category_name` and `category_names` or `population_names` and `population_tags` are provided simultaneously, in which case normalization will ignore the delimited value and always go with the list form.

This adds population fields similar to those already used for categories.

This is detected in validation and, if provided, must be in `YYYY-MM-DD` format.

This adds the `hours` and `npi` fields to the RadRecord format.