Allow dilution in same plate - SpotPlating template in OTProto

[davidcmarkham]

The SpotPlating template currently only allows serial dilution to occur in separate labware. This should be customisable so that the dilution can be done in the source plate (cells plate) and then continue into separate labware once all the wells have been used.

It should also be possible to customise the dilution type so that it doesn't have to be a serial dilution, specifically. There may be issues regarding the minimum transfer volume that the p20 pipette can do which would force an intermediate dilution to be made - the user should be warned of this.