feat(web/website): init

This adds a new Website/Docs for Snix, using Thulite / Doks, which is
mostly hugo and a bit of npm.

Change-Id: Iea10d4068fa783ec0ddd6bcaba5c8d92b1a1168f

web/content/docs/guides/use-as-library.md

@@ -0,0 +1,37 @@
+---
+title: "Use as a library"
+slug: use-as-library
+description: ""
+summary: ""
+date: 2025-03-14T14:14:35+01:00
+lastmod: 2025-03-14T14:14:35+01:00
+draft: false
+weight: 13
+toc: true
+---
+
+If you want to use (parts of) Snix in your own project, you can simply refer to
+it using cargo and specifying the git sources. `cargo` will pin the exact rev
+in `Cargo.lock`. See [The Cargo Book](https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#specifying-dependencies-from-git-repositories) for details.
+
+We do not publish to crates.io yet, due to the interfaces still being a bit
+in flux.
+
+For example, to add `nix-compat`, exposing a lot of Nix data types and formats,
+add the following line to your `Cargo.toml`'s `[dependencies]`':
+
+
+```toml
+nix-compat = { git = "https://git.snix.dev/snix/snix.git" }
+```
+
+
+{{<callout>}}
+Keep in mind some crates have additional requirements on their environment.
+
+For example, `snix-castore` and `snix-store` need to have access to a `protobuf`
+compiler and the proto defintions (setting `PROTO_ROOT` usually).
+`tvix-build` wants `TVIX_BUILD_SANDBOX_SHELL` to be set, etc.
+
+Check each crates' `build.rs` scripts for details.
+{{</callout>}}