Classifier that determines whether a Field should be marked as a `:type/Category` and/or as a `list` Field based on
the number of distinct values it has.

As of Metabase v0.29, the Category now longer has any use inside of the Metabase backend; it is used
only for frontend purposes (e.g. deciding which widget to show). Previously, makring something as a Category meant
that its values should be cached and saved in a FieldValues object. With the changes in v0.29, this is instead
managed by a column called `has_field_values`.

A value of `list` now means the values should be cached. Deciding whether a Field should be a `list` Field is still
determined by the cardinality of the Field, like Category status. Thus it is entirely possibly for a Field to be
both a Category and a `list` Field.

Classifier that infers the special type of a Field based on its name and base type.

Classifier that decides whether a Field should be marked 'No Preview Display'.
(This means Fields are generally not shown in Table results and the like, but
still shown in a single-row object detail page.)

Logic for inferring the special types of *Text* fields based on their TextFingerprints.
These tests only run against Fields that *don't* have existing special types.