add a basic preparation concept

Author: asinghvi17

src/preparations/preparations.jl

@@ -0,0 +1,16 @@
+abstract type AbstractPreparation end
+
+abstract type AbstractPreparationTrait end
+
+function preptrait end
+
+const PrepTuple = Tuple{Vararg{<: AbstractPreparation}}
+
+struct SpatialIndex{IndexType} <: AbstractPreparation
+    index::IndexType
+end
+
+struct SpatialEdgeIndex{IndexType} <: AbstractPreparation
+    index::IndexType
+end
+