Classification - where reference base doesn't match our reference fasta

At the moment this will be flagged as a major HGVS change but it would be better to have finer granularity for the issue

While we're doing this - should normalization be a separate flag or part of this? Both could change the reference though normalization could also change the coordinate and alt.

* New flag type
* Need a new logo maybe something like "!ref"

Something to consider is that maybe in the future we'll have the different patch versions and then handle that, so maybe instead of "our reference fasta" we should store what version we checked, can get this from genome build config I think

Related to #68 - warn when variant ref doesn't match our reference fasta - though that is about variants - this is about classifications