Fan holder/mount for E3D v6 Volcano

I simply remixed SaldoT's very nice E3D fan mount to make it compatible with E3D's longer Volcano nozzles (and the clones). The new part just allows for the side parts to be adjusted up to 8.5 mm lower than the original. I intentionally designed it to have a travel rather than a fixed position, allowing the side fan(s) to be adjusted more accurately. It also allows users to swap between hot-ends without having to replace the fan holder, as this part is compatible with both the E3D V6 and the Vol