Export ship to SLEF option

[leonardofelin]

Describe the enhancement Add export/generate SLEF to the right-click context menu of ships.

Expected behavior When right-clicking the ship name, a new option to export to SLEF, together with the Coriolis and EDSY options.

Considered workarounds This will be a shortcut to exporting to SLEF. Today, we need to open in EDSY and then generate the SLEF.

Additional context This will be very useful in tools like Spansh's Galaxy Plotter, which need the exact ship outfitting to work.

[Rixxan]

Docs: https://inara.cz/elite/inara-impexp-slef/