crostestutils: fix import path and add go.mod

Switching to Go modules mode, which is the default dep
management mode in newer Go versions, requires that all
non standard-library import paths be prefixed with an URL,
so imports like the following will not work anymore:

import "firmware/internal/pkg/dutio"

This is due to the the fact that direct import paths are
now reserved strictly for the Go standard library pkgs
and all non-std pkgs are required to have an URL prefix.

A symlink with the URL path is added to work in GOPATH
mode. It will be dropped when switching to modules mode.

While at it, we also add a go.mod definition which
explicitely lists the dependencies required by the tools.

BUG=b:187795288
TEST=Local builds; CQ.

Cq-Depend: chromium:3666724
Change-Id: I3e993871c6b678fca9928953ba027bc5f0187e7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/3574201
Auto-Submit: Adrian Ratiu <adrian.ratiu@collabora.corp-partner.google.com>
Commit-Queue: Adrian Ratiu <adrian.ratiu@collabora.corp-partner.google.com>
Tested-by: Adrian Ratiu <adrian.ratiu@collabora.corp-partner.google.com>
Reviewed-by: Kevin Shelton <kmshelton@chromium.org>
diff --git a/go/src/firmware/cmd/dut_info/fw_dut_info.go b/go/src/firmware/cmd/dut_info/fw_dut_info.go
index b279a0d..075df0f 100644
--- a/go/src/firmware/cmd/dut_info/fw_dut_info.go
+++ b/go/src/firmware/cmd/dut_info/fw_dut_info.go
@@ -5,8 +5,8 @@
 package main
 
 import (
-	"firmware/internal/pkg/dutio"
 	"fmt"
+	"go.chromium.org/fw-engprod-tools/internal/pkg/dutio"
 	"log"
 	"os"
 	"strings"
diff --git a/go/src/firmware/cmd/lab_triage_helper/fw_lab_triage_helper.go b/go/src/firmware/cmd/lab_triage_helper/fw_lab_triage_helper.go
index 5774658..5f4ecac 100644
--- a/go/src/firmware/cmd/lab_triage_helper/fw_lab_triage_helper.go
+++ b/go/src/firmware/cmd/lab_triage_helper/fw_lab_triage_helper.go
@@ -6,9 +6,9 @@
 
 import (
 	"encoding/json"
-	"firmware/internal/pkg/dutio"
 	"flag"
 	"fmt"
+	"go.chromium.org/fw-engprod-tools/internal/pkg/dutio"
 	"log"
 	"os"
 	"os/exec"
diff --git a/go/src/firmware/go.mod b/go/src/firmware/go.mod
new file mode 100644
index 0000000..15ab94a
--- /dev/null
+++ b/go/src/firmware/go.mod
@@ -0,0 +1,5 @@
+module go.chromium.org/fw-engprod-tools
+go 1.14
+
+require google.golang.org/api v0.60.0
+require golang.org/x/crypto v0.0.0-20220309165113-aa10faf2a1f8
diff --git a/go/src/go.chromium.org/fw-engprod-tools b/go/src/go.chromium.org/fw-engprod-tools
new file mode 120000
index 0000000..3360b29
--- /dev/null
+++ b/go/src/go.chromium.org/fw-engprod-tools
@@ -0,0 +1 @@
+../firmware/
\ No newline at end of file