Fixed #23493 -- Added bilateral attribute to Transform

https://github.com/django/django/pull/3284 is a prerequisite for that PR as `PatternLookup` uses the same mechanism to turn a "transformed" rhs into some SQL as it does for an `F` expression (relying on `pattern_ops`).
The new :attr:`Transform.bilateral <django.db.models.Transform.bilaterial>` attribute allows creating bilaterial transformations. These transformatiosn are applied to both ...