Externalize viteburner as a plugin to allow user to fully control vite configs and workflows

[Tanimodori]

Currently viteburner runs it's own vite server and does not expose much configs, making it impossible for user to add their own plugin. The previous method is used due to the concern that bitburner won't re-connect during vite dev server restarting, which is sometimes annoying. So we need a holder or "proxy" to do that instead of keep the config.