changed the scaling of the egun potential map on axis, so that I do not have to adjust the value of the last data point anymore.

changed the last point of the egun field map to be exactly 300 kV. It gived a very slighly incorrect shape of the field right at the end, but it is a simple way to have round numbers for the energy in the beam envelope.

created the paths and tunes compared to the split initial elbt_1.xml according Thomas' wish going from elbt:vs0 to elbd_fc1