The encrypt/decrypt workhorses are becoming numerous and hard to map to revisions of the FLE protocols.

• mongocrpyt_do_encryption et al
• mongocrypt_fle2_do_encryption et al
• mongocrypt_fle2aead_do_encryption et al

Create a unified interface for encryption/decryption calls associated to FLE revisions to reduce code bloat, reduce opportunity for errors, and make future revisions easier.