feat(tvix/tracing): http propagation for axum

It introduces a new accept_trace function for axum0.7 which can be used
to accept a header trace from a received request. This function can be
used for tonic 0.12 once that version is released, and the specific
`accept_trace` function within `tvix_tracing::propagate::tonic` can then
be removed.

This also integrates http propagation into the nar_bridge crate.

Change-Id: I46dcc797d494bb3977c2633753e7060d88d29129
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11925
Reviewed-by: Brian Olsen <me@griff.name>
Tested-by: BuildkiteCI
Reviewed-by: Simon Hauser <simon.hauser@helsinki-systems.de>
Reviewed-by: flokli <flokli@flokli.de>

tvix/Cargo.lock

@@ -2262,6 +2262,8 @@ dependencies = [
  "tokio-util",
  "tonic",
  "tonic-build",
+ "tower",
+ "tower-http 0.5.2",
  "tracing",
  "tracing-subscriber",
  "tvix-castore",
@@ -4350,6 +4352,23 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "tower-http"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e9cd434a998747dd2c4276bc96ee2e0c7a2eadf3cae88e52be55a05fa9053f5"
+dependencies = [
+ "bitflags 2.4.2",
+ "bytes",
+ "http 1.1.0",
+ "http-body 1.0.0",
+ "http-body-util",
+ "pin-project-lite",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
 [[package]]
 name = "tower-layer"
 version = "0.3.2"
@@ -4755,7 +4774,7 @@ dependencies = [
  "tonic-build",
  "tonic-reflection",
  "tower",
- "tower-http",
+ "tower-http 0.4.4",
  "tracing",
  "tracing-indicatif",
  "tvix-castore",
@@ -4768,6 +4787,7 @@ dependencies = [
 name = "tvix-tracing"
 version = "0.1.0"
 dependencies = [
+ "axum 0.7.5",
  "http 0.2.11",
  "indicatif",
  "lazy_static",