PHPLIB-843: Support clusteredIndex option for createCollection

Fixes preparation of database, collection, and index enumeration results. The new spec tests are the first to assert these results (including those for legacy test runners).

Sync collection-management spec tests with mongodb/specifications@d145882, which also covers PHPLIB-856

Author: jmikola

source/includes/apiargs-MongoDBDatabase-method-createCollection-option.yaml

@@ -27,6 +27,23 @@ interface: phpmethod
 operation: ~
 optional: true
 ---
+arg_name: option
+name: clusteredIndex
+type: document
+description: |
+  A clustered index specification. See
+  :manual:`Clustered Collections </core/clustered-collections>` or the
+  :manual:`create </reference/command/create>` command documentation for more
+  information.
+
+  This option is available in MongoDB 5.3+ and will result in an exception at
+  execution time if specified for an older server version.
+
+  .. versionadded:: 1.13
+interface: phpmethod
+operation: ~
+optional: true
+---
 source:
   file: apiargs-common-option.yaml
   ref: collation