tools: Migrate remaining tools to gobin

Replace ./scripts/install_tool.sh with `gobin`, such that we have
consistent handling for all tools needed for build and consistent
versioning within ./tools/mod/go.mod.

Side changes:
  - Expose /scripts/fix.sh that fixes formatting and bom across modules
  - Expose *.sh variants of scripts like build and ./test (first step
towards replacement).
  - Make stderr output of commands explicit and make commands use
different color than callouts.

scripts/updatebom.sh

@@ -1,17 +1,38 @@
 #!/usr/bin/env bash
 
 set -e
+source ./scripts/test_lib.sh
 
-if ! [[ "$0" =~ scripts/updatebom.sh ]]; then
-	echo "must be run from repository root"
-	exit 255
-fi
+function bom_fixlet {
+  log_callout "generating bill-of-materials.json"
 
-./scripts/install_tool.sh github.com/coreos/license-bill-of-materials
+  cp go.mod go.mod.tmp
+  cp go.sum go.sum.tmp
 
-echo "generating bill-of-materials.json"
-license-bill-of-materials \
-    --override-file ./bill-of-materials.override.json \
-    go.etcd.io/etcd/v3 go.etcd.io/etcd/v3/etcdctl > bill-of-materials.json
+  local modules
+  # shellcheck disable=SC2207
+  modules=($(modules_exp))
 
-echo "generated bill-of-materials.json"
+  if GOFLAGS=-mod=mod run_go_tool "github.com/coreos/license-bill-of-materials" \
+      --override-file ../bill-of-materials.override.json \
+      "${modules[@]}" > ../bill-of-materials.json.tmp; then
+    cp ../bill-of-materials.json.tmp ../bill-of-materials.json
+    log_success "bom refreshed"
+  else
+    log_error "FAIL: bom refreshing failed"
+  fi
+  mv go.mod.tmp go.mod
+  mv go.sum.tmp go.sum
+}
+
+function bom_fix {
+  # We regenerate bom from the tests directory, as it's a module
+  # that depends on all other modules, so we can generate comprehensive content.
+  # TODO: Migrate to root module, when root module depends on everything (including server & tests).
+  run_for_module "./tests" bom_fixlet
+}
+
+# only build when called directly, not sourced
+if [[ "$0" =~ updatebom.sh$ ]]; then
+  bom_fix
+fi