feat: Add "coder" CLI (#221)

* feat: Add "coder" CLI

* Add CLI test for login

* Add "bin/coder" target to Makefile

* Update promptui to fix race

* Fix error scope

* Don't run CLI tests on Windows

* Fix requested changes

cli/clitest/clitest.go

@@ -0,0 +1,38 @@
+package clitest
+
+import (
+	"bufio"
+	"io"
+	"testing"
+
+	"github.com/spf13/cobra"
+
+	"github.com/coder/coder/cli"
+	"github.com/coder/coder/cli/config"
+)
+
+func New(t *testing.T, args ...string) (*cobra.Command, config.Root) {
+	cmd := cli.Root()
+	dir := t.TempDir()
+	root := config.Root(dir)
+	cmd.SetArgs(append([]string{"--global-config", dir}, args...))
+	return cmd, root
+}
+
+func StdoutLogs(t *testing.T) io.Writer {
+	reader, writer := io.Pipe()
+	scanner := bufio.NewScanner(reader)
+	t.Cleanup(func() {
+		_ = reader.Close()
+		_ = writer.Close()
+	})
+	go func() {
+		for scanner.Scan() {
+			if scanner.Err() != nil {
+				return
+			}
+			t.Log(scanner.Text())
+		}
+	}()
+	return writer
+}