feat(tvix/store/proto): use Bytes instead of Vec<u8>

Makes use of https://github.com/tokio-rs/prost/pull/341, which makes our
bytes field cheaper to clone.

It's a bit annoying to configure due to
https://github.com/hyperium/tonic/issues/908, but the workaround does
get the job done.

Change-Id: I25714600b041bb5432d3adf5859b151e72b12778
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8975
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>

corp/tvixbolt/Cargo.lock

@@ -52,6 +52,12 @@ version = "3.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0d261e256854913907f67ed06efbc3338dfe6179796deefc1ff763fc1aee5535"
 
+[[package]]
+name = "bytes"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89b2fd2a0dcf38d7971e2194b6b6eebab45ae01067456a7fd93d5547a61b70be"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -790,6 +796,7 @@ dependencies = [
 name = "tvix-eval"
 version = "0.1.0"
 dependencies = [
+ "bytes",
  "codemap",
  "codemap-diagnostic",
  "dirs",