expand checks in `validate_for_write()`

[wibeasley]

• [x] add a convert_logical_to_integer parameter . If it's true, it won't warn about

  The REDCap API does not automatically convert boolean values to 0/1 values.

• [x] redcap_repeat_instance should be an integer
• [x] validate_uniqueness(): check for unique combinations of record_id, redcap_event_name, redcap_repeat_instrument, &
• [x] validate_data_frame_inherits()
• [x] validate_field_names()
• [x] validate_record_id_name()
• [x] validate_repeat_instance()
• [x] validate_no_logical()