Adding quad length to yaml files

[nneveu]

Is your feature request related to a problem? Please describe.
In order to do emittance measurements, we need to know the effective length of the quad.

Describe the solution you'd like
Three steps are needed to add this to lcls-tools:

• Update yaml generation script to pull quad length from cvs database.
• Run generation script to update all yaml files.
• Update magnet device class to include quad length property.

Describe alternatives you've considered
Not including in device class, this would require the GUI or alternative method of grabbing the quad length.

[nneveu]

Maybe we should add this somewhere for when we need to generate the yamls:

from lcls_tools.common.devices.yaml.write import YAMLWriter

writer = YAMLWriter()
areas = writer.machine_areas
[writer.write_yaml_file(area) for area in areas] 

[MattKing06]

Maybe we should add this somewhere for when we need to generate the yamls:

from lcls_tools.common.devices.yaml.write import YAMLWriter

writer = YAMLWriter()
areas = writer.machine_areas
[writer.write_yaml_file(area) for area in areas] 

This could be added to generate.py in the

if __name__ == '__main__':
    ...

So you can just run python generate.py

[nneveu]

@phys-cgarnier please add Matt's suggestion to your branch for this PR. Thanks!