feat(tvix/tools/crunch-v2): init

This is a tool for ingesting subsets of cache.nixos.org into its own flattened castore format.
Currently, produced chunks are not preserved, and this purely serves as a way of measuring
compression/deduplication ratios for various chunking and compression parameters.

Change-Id: I3983af02a66f7837d76874ee0fc8b2fab62ac17e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10486
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

tvix/tools/crunch-v2/src/lib.rs

@@ -0,0 +1,10 @@
+use lazy_static::lazy_static;
+
+pub mod proto {
+    include!(concat!(env!("OUT_DIR"), "/tvix.flatstore.v1.rs"));
+}
+
+lazy_static! {
+    static ref DB: sled::Db = sled::open("crunch.db").unwrap();
+    pub static ref FILES: sled::Tree = DB.open_tree("files").unwrap();
+}