Improve random system generation, load custom systems from JSON

data/systems/00_sol.lua

@@ -159,12 +159,15 @@ local mars = CustomSystemBody:new('Mars', 'PLANET_TERRESTRIAL')
 
 local mars_starports = {
 	CustomSystemBody:new('Bradbury Landing', 'STARPORT_SURFACE')
+		:seed(201299135)
 		:latitude(math.deg2rad(-4.5895))
 		:longitude(math.deg2rad(-137.4417)),
 	CustomSystemBody:new('Cydonia', 'STARPORT_SURFACE')
+		:seed(2874781459)
 		:latitude(math.deg2rad(-29))
 		:longitude(math.deg2rad(124)),
 	CustomSystemBody:new('Olympus Mons', 'STARPORT_SURFACE')
+		:seed(3046926584)
 		:latitude(math.deg2rad(25.60955))
 		:longitude(math.deg2rad(-41.35269)),
 	CustomSystemBody:new('Mars High', 'STARPORT_ORBITAL')

data/systems/01_epsilon_eridani.lua

@@ -74,6 +74,7 @@ local newhope = CustomSystemBody:new('New Hope', 'PLANET_TERRESTRIAL')
 
 	local newhope_starports = {
 	CustomSystemBody:new('Itzalean', 'STARPORT_SURFACE')
+		:seed(795500669)
 		:latitude(math.deg2rad(0.0))
 		:longitude(math.deg2rad(45.864)),
 	CustomSystemBody:new('New Hope', 'STARPORT_SURFACE')

data/systems/02_local_stars.lua

@@ -1,7 +1,7 @@
 -- Copyright © 2008-2023 Pioneer Developers. See AUTHORS.txt for details
 -- Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
-CustomSystem:new('GJ 1075',{'STAR_K'}):add_to_sector(2,-1,-4,v(0.451,0.409,0.034))
+-- CustomSystem:new('GJ 1075',{'STAR_K'}):add_to_sector(2,-1,-4,v(0.451,0.409,0.034))
 CustomSystem:new('NN 3707',{'STAR_M'}):add_to_sector(-1,3,-1,v(0.845,0.512,0.054))
 CustomSystem:new('NN 3253',{'STAR_M'}):add_to_sector(3,-2,1,v(0.185,0.023,0.148))
 CustomSystem:new('Gliese 766',{'STAR_M','STAR_M'}):add_to_sector(-4,-2,1,v(0.511,0.265,0.998))