chore(nint): move from //users/sterni to //nix

Since //web/bubblegum depends on nint, we need to move it to a non user
directory to conform with the policy established via cl/3434.
Note that this likely doesn't mean greater stability (which isn't
really implied in depot anyways), since I still would like to use a more
elaborate calling convention to allow for additional useful features.

Change-Id: I616f905d8df13e3363674aab69a797b0d39fdd79
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3506
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

default.nix

@@ -34,11 +34,6 @@ let
       # TODO(tazjin): Can this one be removed somehow?
       [ "ops" "nixos" ]
       [ "ops" "machines" "all-systems" ]
-
-      # //web/bubblegum has examples using //users/sterni, they should
-      # probably be in the user folder instead with a link there.
-      # TODO(sterni): Clean this up.
-      [ "web" "bubblegum" ]
     ]
     then args
     else args // {