Background
See WRITING-9838.

Scope
Try to dynamically load csfle from mongocrypt_init in libmongocrypt.
If csfle is not found, fallback to existing behavior and try to use mongocryptd.
If csfle is found and the csfle major version is compatible, libmongocrypt must use csfle for CSFLE and must not require or use mongocryptd.
If csfle is found and the csfle major version is unsupported, mongocrypt_init must return an error.