opam: migrate 14 hand-maintained packages to dune-generated
Moves package metadata into dune-project for kdf, monopam-info,
ocaml-ax25, ocaml-collision, ocaml-crypto (4 subpackages), ocaml-csv,
ocaml-respond, ocaml-sdnv, ocaml-tls (2 subpackages), ocaml-vec3, and
ocaml-x509, and flags each .opam with the generated-by-dune header.
Running dune build after the ocaml-toml build break is resolved will
regenerate the .opam files from dune-project and reveal any
canonical-form drift in a separate commit.