DRIVERS-2312: add new method ClientEncryption.CreateEncryptedCollection https://github.com/mongodb/specifications/blob/master/source/client-side-encryption/client-side-encryption.rst#create-encrypted-collection-helper add prose test from section #21 https://github.com/mongodb/specifications/tree/master/source/client-side-encryption/tests#automatic-data-encryption-keys document ClientEncryption.CreateEncryptedCollection as "Public Technical Preview". Follow the convention taken with DRIVERS-2349. The relevant spec changes: the main spec change (note that eventually it was determined that the GetEncryptedFields helper is irrelevant to this ticket) and prose tests https://github.com/mongodb/specifications/commit/02c6e3fa7dbc3a64e5312ef820e0f1779069cadb more prose tests https://github.com/mongodb/specifications/commit/64cf83b604107edffe9f75eb91b0690d5daa8b7c more prose tests https://github.com/mongodb/specifications/commit/10122e797c6eeb5e96007ee1ca3ca0dbf0374d95 prose tests clarification https://github.com/mongodb/specifications/commit/f6ecec6a70226b53f181a25c6b404be342735c1c spec fix https://github.com/mongodb/specifications/commit/a0bb4994ec9fb661d957cfaf7af5fc4fc7858484 spec fix https://github.com/mongodb/specifications/commit/0a44c5bb3133d7b3e156276a9cba45daccb9266d spec and test changes https://github.com/mongodb/specifications/commit/479f4bddf517eb6d90abdfc71043b711ccc1f867