Add new Data Structure Nodes to Geonodes attributes such as lists, dicttionaries, hash tables.

If the nodes in Geonodes could store and manipulate arrays of the current data types (float, bool, string, vector, ...) on each element we would have greater flexibility. We may want to declare a list of colours and cycle through them as a palette, or bin all the verts in a point cloud in a boundary volume hash table and make our own marching cubes. Or have a dictionary of geometry we could call with keys (strings) and create a simple L-System. If we had [Create/Read/Update/Delete] Data Structure nodes a much greater freedom for procedural creation would be achieved.