remove LazyQuery.jl and StructuredQuery.jl

LazyQuery.jl websites gives 404 and StructuredQuery.jl hasn't been updated for 3 years and only works on 0.5

Author: xiaodaigh

README.md

@@ -28,7 +28,7 @@ The package currently provides working implementations for in-memory data source
 Query is heavily inspired by [LINQ](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/index), in fact right now the package is largely an implementation of the [LINQ](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/indexq) part of the [C# specification](https://msdn.microsoft.com/en-us/library/ms228593.aspx). Future versions of Query will most likely add features that are not found in the original [LINQ](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/index) design.
 
 ## Alternatives
-[Query.jl](https://github.com/queryverse/Query.jl) is not the only julia initiative for querying data, there are many other packages that have similar goals. Take a look at [DataFramesMeta.jl](https://github.com/JuliaStats/DataFramesMeta.jl), [StructuredQueries.jl](https://github.com/davidagold/StructuredQueries.jl), [LazyQuery.jl](https://github.com/bramtayl/LazyQuery.jl) and [SplitApplyCombine.jl](https://github.com/JuliaData/SplitApplyCombine.jl). *If I missed other initiatives, please let me know and I'll add them to this list!*
+[Query.jl](https://github.com/queryverse/Query.jl) is not the only julia initiative for querying data, there are many other packages that have similar goals. Take a look at [DataFramesMeta.jl](https://github.com/JuliaStats/DataFramesMeta.jl), and [SplitApplyCombine.jl](https://github.com/JuliaData/SplitApplyCombine.jl). *If I missed other initiatives, please let me know and I'll add them to this list!*
 
 ## Installation