Add patches for directories-next/option-ext

The rational is detailed in the root Cargo.toml.

While I don't personally mind MPL dependencies, even if I don't prefer them
(they're allowed in the deny.toml for a reason), I do mind the pointless scope
creep and wish to highlight how little it actually used from the crate by
re-defining it as the single function.

We could also fork directories-next, or directories, and remove the usage of
option-ext per https://github.com/dirs-dev/dirs-sys-rs/issues/24, yet that'd be
a much larger task than what was done here.

In the future, it may be beneficial to submit a PR to wasmtime replacing
directories-next with home, a cargo-team maintained library to get the home
directory and associated folders. An example migration can be found at
https://github.com/harryfei/which-rs/pull/80.

patches/option-ext/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "option-ext"
+version = "0.2.0"
+description = "Non-MPL option-ext with the exactly needed API for directories"
+license = "MIT"
+repository = "https://github.com/serai-dex/serai/tree/develop/patches/option-ext"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = []
+edition = "2021"
+rust-version = "1.74"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]