Interstage pre-alignment

[carlandreaslindstrom]

This PR adds a method for pre-aligning the plasma lenses to compensate for ISR and CSR kicks in the interstage.

[carlandreaslindstrom]

Example of running the pre-alignment procedure over many stages (at increasing energy):

Interstage pre-alignment: building response matrix...
>> Before: x = -8.24 µm, -0.05 mrad  ->  After: x = -0.02 µm, -0.00 mrad
>> Ideal offset: lens 1 = -2.42 µm, lens 2 = 2.85 µm
Interstage pre-alignment: building response matrix...
>> Before: x = 3.78 µm, 0.02 mrad  ->  After: x = 0.00 µm, 0.00 mrad
>> Ideal offset: lens 1 = 1.20 µm, lens 2 = -1.23 µm
Interstage pre-alignment: building response matrix...
>> Before: x = -2.44 µm, -0.01 mrad  ->  After: x = -0.00 µm, -0.00 mrad
>> Ideal offset: lens 1 = -0.73 µm, lens 2 = 0.84 µm
Interstage pre-alignment: building response matrix...
>> Before: x = 1.76 µm, 0.01 mrad  ->  After: x = 0.00 µm, 0.00 mrad
>> Ideal offset: lens 1 = 0.55 µm, lens 2 = -0.59 µm
Interstage pre-alignment: building response matrix...
>> Before: x = -1.32 µm, -0.00 mrad  ->  After: x = -0.00 µm, -0.00 mrad
>> Ideal offset: lens 1 = -0.38 µm, lens 2 = 0.48 µm