feat(tvl-kit): Expose lazy-deps

This adds the //nix/lazy-deps tool at //lazy-deps in tvl-kit.

A CI step is added for the kit that uses this to lazily build an
example tool (magrathea).

Change-Id: Ibd6d69c83b87bd6e0766942d73297621f2593113
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5514
Tested-by: BuildkiteCI
Reviewed-by: ezemtsov <eugene.zemtsov@gmail.com>

views/kit/workspace.josh

@@ -3,6 +3,7 @@ besadii = :/ops/besadii
 :/nix:[
     ::buildGo/
     ::buildkite/
+    ::lazy-deps/
     ::readTree/
 ]
 :/third_party:[