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>

database/time.go

@@ -0,0 +1,8 @@
+package database
+
+import "time"
+
+// Now returns a standardized timezone used for database resources.
+func Now() time.Time {
+	return time.Now().UTC()
+}