Creates a hash map. A hash map is a container that maps strings (called keys) to arbitrary values (cells, arrays or strings).
Keys in a hash map are unique so there is no more than one entry in the map for any given key.
Insertion, deletion, and lookup in a hash map are all considered to be fast operations, amortized to O(1), or constant time.
New Map handle, which must be freed via TrieDestroy()