Core: Add hashing support to Array data structure

Implements hashing with the same implementation as the `Vector` data
structure. Hashing requested in PR review of #145531.

Pull Request: https://projects.blender.org/blender/blender/pulls/145689

source/blender/blenlib/BLI_array.hh

@@ -355,6 +355,16 @@ class Array {
     return IndexRange(size_);
   }
 
+  uint64_t hash() const
+  {
+    return this->as_span().hash();
+  }
+
+  static uint64_t hash_as(const Span<T> values)
+  {
+    return values.hash();
+  }
+
   friend bool operator==(const Array &a, const Array &b)
   {
     return a.as_span() == b.as_span();