Add new `FssBodySignals` event

[Tkael]

What happens now

Information on planet surface signals is only available after mapping a body

What I'd like to happen

Information on planet surface signals from an FSS scan. Don't repeat the same already-discovered signals when mapping a body.

How it can happen

A new "FssBodySignals" event has been added with info on types of signals found on a planet (biological & geological signals only).

EDDI Version

4.0.1-b2

[Tkael]

This could be helpful for #2212.

[Tkael]

New FSSBodySignals event (written after an FSS scan) - includes biological and geological signals only

{ "timestamp":"2021-07-30T21:53:10Z", "event":"FSSBodySignals", "BodyName":"HIP 65165 B 6", "BodyID":10, "SystemAddress":1625385093475, "Signals":[ { "Type":"$SAA_SignalType_Biological;", "Type_Localised":"Biological", "Count":1 }, { "Type":"$SAA_SignalType_Geological;", "Type_Localised":"Geological", "Count":2 } ] }

Old SAASignalsFound event (written after mapping) - includes nonbiological signals

{ "timestamp":"2021-07-30T22:08:15Z", "event":"SAASignalsFound", "BodyName":"HIP 65165 B 6", "SystemAddress":1625385093475, "BodyID":10, "Signals":[ { "Type":"$SAA_SignalType_Biological;", "Type_Localised":"Biological", "Count":1 }, { "Type":"$SAA_SignalType_Geological;", "Type_Localised":"Geological", "Count":2 }, { "Type":"$SAA_SignalType_Human;", "Type_Localised":"Human", "Count":4 } ] }