Update to use jll artifact

[jaakkor2]

• uses jll build by https://github.com/JuliaPackaging/Yggdrasil/tree/master/L/LibSpatialIndex
  • requires Julia v1.3
  • artifact is located at https://github.com/JuliaBinaryWrappers/LibSpatialIndex_jll.jl
• https://github.com/JuliaGeo/LibSpatialIndexBuilder not used anymore

[visr]

This is great, thanks! This is the last build in JuliaGeo to make the switch. Left a few minor comments. Could you also add a line to the readme saying that libspatialindex builds are provided, linking to both https://github.com/JuliaPackaging/Yggdrasil/tree/master/L/LibSpatialIndex and https://github.com/JuliaBinaryWrappers/LibSpatialIndex_jll.jl?

@MaximeBouton are you ok with merging this, and archiving https://github.com/JuliaGeo/LibSpatialIndexBuilder?

[MaximeBouton]

This is great, thanks!
@visr I am fine with archiving the other repo.