feat: Add authentication and personal user endpoint (#29)

* feat: Add authentication and personal user endpoint

This contribution adds a lot of scaffolding for the database fake
and testability of coderd.

A new endpoint "/user" is added to return the currently authenticated
user to the requester.

* Use TestMain to catch leak instead

* Add userpassword package

* Add WIP

* Add user auth

* Fix test

* Add comments

* Fix login response

* Fix order

* Fix generated code

* Update httpapi/httpapi.go

Co-authored-by: Bryan <bryan@coder.com>

Co-authored-by: Bryan <bryan@coder.com>

coderd/coderdtest/coderdtest.go

@@ -0,0 +1,59 @@
+package coderdtest
+
+import (
+	"context"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"cdr.dev/slog/sloggers/slogtest"
+	"github.com/coder/coder/coderd"
+	"github.com/coder/coder/codersdk"
+	"github.com/coder/coder/database/databasefake"
+)
+
+// Server represents a test instance of coderd.
+// The database is intentionally omitted from
+// this struct to promote data being exposed via
+// the API.
+type Server struct {
+	Client *codersdk.Client
+	URL    *url.URL
+}
+
+// New constructs a new coderd test instance.
+func New(t *testing.T) Server {
+	// This can be hotswapped for a live database instance.
+	db := databasefake.New()
+	handler := coderd.New(&coderd.Options{
+		Logger:   slogtest.Make(t, nil),
+		Database: db,
+	})
+	srv := httptest.NewServer(handler)
+	u, err := url.Parse(srv.URL)
+	require.NoError(t, err)
+	t.Cleanup(srv.Close)
+
+	client := codersdk.New(u)
+	_, err = client.CreateInitialUser(context.Background(), coderd.CreateUserRequest{
+		Email:    "testuser@coder.com",
+		Username: "testuser",
+		Password: "testpassword",
+	})
+	require.NoError(t, err)
+
+	login, err := client.LoginWithPassword(context.Background(), coderd.LoginWithPasswordRequest{
+		Email:    "testuser@coder.com",
+		Password: "testpassword",
+	})
+	require.NoError(t, err)
+	err = client.SetSessionToken(login.SessionToken)
+	require.NoError(t, err)
+
+	return Server{
+		Client: client,
+		URL:    u,
+	}
+}