Export SLEF support

[spectrapulse]

It's very nice that the ability to import SLEF format's into Coriolis (added by with #592)but I've been looking for a way to also export it out in the same format which seems to be missing?

It would be useful if I could also export it out again so I can use loadout comparison's and set a target loadout on Inara.

[alex-williams]

Currently the feature to export to JSON exists, but not SLEF. SLEF Export is on the to-do list.

[khaosdoctor]

Hey! I noticed no one picked this up, so I forked the repo and I'm working on it :) I hope to have something ready soon!

[khaosdoctor]

Done :D @alex-williams @spectrapulse if you could please take a look 😄