third_party/rust: initialize, add mdbook

As we want to use [mdbook](https://github.com/rust-lang/mdBook) to build
documentation, we now have to pull it into the monorepo, alongside
support for Rust in general.

Testing plan: bazel run //third_party/rust:cargo_bin_mdbook. The CI
should also pick this up now.

Change-Id: I6cf5d02d926bb0de61a5c882828accd35f3a1076
Reviewed-on: https://review.monogon.dev/c/monogon/+/201
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/third_party/rust/cargo/remote/BUILD.hyper-0.13.10.bazel b/third_party/rust/cargo/remote/BUILD.hyper-0.13.10.bazel
new file mode 100644
index 0000000..b4fc3d2
--- /dev/null
+++ b/third_party/rust/cargo/remote/BUILD.hyper-0.13.10.bazel
@@ -0,0 +1,131 @@
+"""
+@generated
+cargo-raze crate build file.
+
+DO NOT EDIT! Replaced on runs of cargo-raze
+"""
+
+# buildifier: disable=load
+load("@bazel_skylib//lib:selects.bzl", "selects")
+
+# buildifier: disable=load
+load(
+    "@rules_rust//rust:rust.bzl",
+    "rust_binary",
+    "rust_library",
+    "rust_test",
+)
+
+package(default_visibility = [
+    # Public for visibility by "@raze__crate__version//" targets.
+    #
+    # Prefer access through "//third_party/rust/cargo", which limits external
+    # visibility to explicit Cargo.toml dependencies.
+    "//visibility:public",
+])
+
+licenses([
+    "notice",  # MIT from expression "MIT"
+])
+
+# Generated Targets
+
+# Unsupported target "body" with type "bench" omitted
+
+# Unsupported target "connect" with type "bench" omitted
+
+# Unsupported target "end_to_end" with type "bench" omitted
+
+# Unsupported target "pipeline" with type "bench" omitted
+
+# Unsupported target "server" with type "bench" omitted
+
+# Unsupported target "client" with type "example" omitted
+
+# Unsupported target "client_json" with type "example" omitted
+
+# Unsupported target "echo" with type "example" omitted
+
+# Unsupported target "gateway" with type "example" omitted
+
+# Unsupported target "hello" with type "example" omitted
+
+# Unsupported target "http_proxy" with type "example" omitted
+
+# Unsupported target "multi_server" with type "example" omitted
+
+# Unsupported target "params" with type "example" omitted
+
+# Unsupported target "send_file" with type "example" omitted
+
+# Unsupported target "service_struct_impl" with type "example" omitted
+
+# Unsupported target "single_threaded" with type "example" omitted
+
+# Unsupported target "state" with type "example" omitted
+
+# Unsupported target "tower_client" with type "example" omitted
+
+# Unsupported target "tower_server" with type "example" omitted
+
+# Unsupported target "upgrades" with type "example" omitted
+
+# Unsupported target "web_api" with type "example" omitted
+
+rust_library(
+    name = "hyper",
+    srcs = glob(["**/*.rs"]),
+    aliases = {
+    },
+    crate_features = [
+        "default",
+        "runtime",
+        "socket2",
+        "stream",
+        "tcp",
+    ],
+    crate_root = "src/lib.rs",
+    crate_type = "lib",
+    data = [],
+    edition = "2018",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    tags = [
+        "cargo-raze",
+        "manual",
+    ],
+    version = "0.13.10",
+    # buildifier: leave-alone
+    deps = [
+        "@raze__bytes__0_5_6//:bytes",
+        "@raze__futures_channel__0_3_15//:futures_channel",
+        "@raze__futures_core__0_3_15//:futures_core",
+        "@raze__futures_util__0_3_15//:futures_util",
+        "@raze__h2__0_2_7//:h2",
+        "@raze__http__0_2_4//:http",
+        "@raze__http_body__0_3_1//:http_body",
+        "@raze__httparse__1_4_1//:httparse",
+        "@raze__httpdate__0_3_2//:httpdate",
+        "@raze__itoa__0_4_7//:itoa",
+        "@raze__pin_project__1_0_7//:pin_project",
+        "@raze__socket2__0_3_19//:socket2",
+        "@raze__tokio__0_2_25//:tokio",
+        "@raze__tower_service__0_3_1//:tower_service",
+        "@raze__tracing__0_1_26//:tracing",
+        "@raze__want__0_3_0//:want",
+    ] + selects.with_or({
+        # cfg(any(target_os = "linux", target_os = "macos"))
+        (
+            "@rules_rust//rust/platform:x86_64-unknown-linux-gnu",
+        ): [
+        ],
+        "//conditions:default": [],
+    }),
+)
+
+# Unsupported target "client" with type "test" omitted
+
+# Unsupported target "integration" with type "test" omitted
+
+# Unsupported target "server" with type "test" omitted