Feature Request: Using the QCF filter with existing assimilation experiments

[hkershaw-brown]

This is a note for the QCF development branch.
Feature Request:

Use case:
User starting from existing assimilations with restart files that have 'out of bounds' values.
User runs quantile_methods filter, which will then error out.

Suggested solution, clamp out of bounds values for initial QCF cycle (no need to clamp after this initial cycle).