Webserver improvements

[promise]

These are only mild suggestions and would improve customization with plugins interacting with the webserver by a lot.

• moving the ./src/modules/webserver.js outside of the modules folder, to not confuse with actual modules- this file is more of a constant or an utility and it would make more sense to have it in a utils folder, or even just in ./src might be the cleanest
• move code from the webserver.js file to ./src/modules/webserverPlugin.js, it makes more sense to have it there. This also opens up for more plugin customization as we don't need to remove specific code from the webserver.js file to customize our webserver, but instead can just replace the webserverPlugin.js.