refactor(ore-rs): drop dead convert module

`ToOrderedInteger` / `FromOrderedInteger` were the legacy bridge from
`f64` to a lex-orderable `u64` plaintext. Now that `OreEncrypt for f64`
goes through `orderable_bytes::ToOrderableBytes`, the trait and its
sole impl are unused. Remove the module and its `mod convert;` entry.

Author: freshtonic

packages/ore-rs/src/convert.rs

@@ -139,7 +139,6 @@
 #[cfg(feature = "chrono")]
 mod chrono;
 mod ciphertext;
-mod convert;
 #[cfg(feature = "decimal")]
 mod decimal;
 mod encrypt;