deprecate DES_ENCRYPT/DECRYPT functions

Hopefully nobody uses them anymore.

https://en.wikipedia.org/wiki/Triple_DES:

The Data Encryption Standard's (DES) 56-bit key is no longer considered adequate in the face of modern cryptanalytic techniques and supercomputing power. A CVE released in 2016, CVE-2016-2183 disclosed a major security vulnerability in DES and 3DES encryption algorithms. This CVE, combined with the inadequate key size of DES and 3DES, NIST has deprecated DES and 3DES for new applications in 2017, and for all applications by 2023. It has been replaced with the more secure, more robust AES.