Rename 'anonymize' package

[stephen-soltesz]

M-Lab is using a colloquial sense of "anonymize" that means "de-identify" which differs from the technical definition of anonymization from https://www.rfc-editor.org/rfc/rfc6973#section-6.1.1 which depends on non-uniqueness (multiple events). This difference is confusing to some audiences, and may imply more than what this package actually does.

See also: #154 (review)

The anonymize package should be renamed to more clearly match its intention and application.