ts: Ensure mutate() and genomeEdit() DNA changes are stored in tree sequence mutation table

[gregorgorjanc]

We have mutation() and editGenome() functions in AlphaSimR. These are limited just to tracked sites within AlphaSimR current genome structure, so not a full-fledged-mutation-setup we might want to implement with once we have tree sequence recording implemented. Before we do this last part, we will want to ensure that mutation() and editGenome() functions also store the DNA changes also in the ts mutation table. This will be a nice pathway to move towards implementing full-fledged-mutation-setup.