Improved Canonicalization

[PsypherPunk]

The current status of Wayback's canonicalization is documented here.

This should be amended to be similar to that of Heritrix: i.e. a configurable series of steps, broadly outlined here, ideally sharing the same codebase to do so.

[kris-sigur]

There is one element of canonicalization where Heritrix and Wayback will need to differ and that is that Wayback will need to handle changing canonicalization rules over time!