feat(nix-compat/{aterm,derivation}): init parser

This provides a nom-based parser for Nix derivations in ATerm format,
which can be reached via `Derivation::from_aterm_bytes`.

Some of the lower-level ATerm primitives are moved into a (new) aterm
module, and some more higher-level ones that construct derivation-
specific types.

Also, move the escape_bytes function into there, this is a generic ATerm
thing.

Change-Id: I2b03b8a1461c7ea2fcb8640c2fc3d1fa3ea719fb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9730
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI

tvix/Cargo.lock

@@ -1340,6 +1340,12 @@ version = "0.3.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6877bb514081ee2a7ff5ef9de3281f14a4dd4bceac4c09388074a6b5df8a139a"
 
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
 [[package]]
 name = "miniz_oxide"
 version = "0.7.1"
@@ -1427,7 +1433,9 @@ dependencies = [
  "data-encoding",
  "futures",
  "futures-util",
+ "glob",
  "lazy_static",
+ "nom",
  "serde",
  "serde_json",
  "sha2",
@@ -1436,6 +1444,16 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "nom8"
 version = "0.2.0"