This commit adds the following changes:
- autostart enable|disable => autostart set|unset
- autostart enable now accepts a more natual schedule format: <time> <days-of-week> <location>
- autostart show now shows configured timezone
- 🎉 automatic timezone detection across mac, windows, linux 🎉Fixes#1647
* Changes all public-facing codersdk types to use a plain int64 (milliseconds) instead of time.Duration.
* Makes autostart_schedule a *string as it may not be present.
* Adds a utils/ptr package with some useful methods.
