refactor(tvix/nar-bridge): mv nar-bridge{,-http}

Rename the nar-bridge CLI to nar-bridge-http, because it's the one
spinning up an http server.

Change-Id: I0fb75c50e4299272a128dd5ecaa4be8f06fa3dbe
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9538
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>

tvix/boot/README.md

@@ -43,9 +43,9 @@ Potentially copy some data into tvix-store (via nar-bridge):
 
 ```
 mg run //tvix:store -- daemon &
-mg run //tvix:nar-bridge -- &
+$(mg build //tvix:nar-bridge)/bin/nar-bridge-http &
 rm -Rf ~/.cache/nix; nix copy --to http://localhost:9000\?compression\=none $(mg build //third_party/nixpkgs:hello)
-pkill nar-bridge; pkill tvix-store
+pkill nar-bridge-http; pkill tvix-store
 ```
 
 #### Interactive shell

tvix/nar-bridge/.gitignore

@@ -1 +1 @@
-/nar_bridge
+/nar-bridge-http

tvix/nar-bridge/cmd/nar-bridge-http/main.go

@@ -55,7 +55,7 @@ func main() {
 		30,
 	)
 
-	log.Printf("Starting nar-bridge at %v", cli.ListenAddr)
+	log.Printf("Starting nar-bridge-http at %v", cli.ListenAddr)
 	go s.ListenAndServe(cli.ListenAddr)
 
 	// listen for the interrupt signal.