Add anonymization to BIDS Incremental

[spolcyn]

Currently, anonymization is handled at the DICOM level. However, it could be easier for users to handle anonymization at the stage they make a BIDS Incremental.

Anonymization would be added in the BIDS Incremental constructor (__init__). It would use the attributesToAnonymize list in imageHandling.py in combination with the makeDicomFieldBidsCompatible method to remove the fields from the imageMetadata dictionary.

Ideally, this behavior should be controlled by a constructor flag anonymizeMetadata.

Additional Enhancement:

1. Have the user specify what fields to remove, or what 'sets' of fields to remove (e.g., location data, scanner data, personal data)