feat(tazjin/rlox): Add basic program structure

... as well as a Nix derivation, because why not.

Change-Id: Iaf2591ab72676fe0732c3f807b3aa0cff13fb4ef
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2143
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/rlox/src/interpreter.rs

@@ -0,0 +1,4 @@
+// Run some Lox code and print it to stdout
+pub fn run(_code: &str) {
+    println!("no interpreter yet, sorry")
+}