Add docker build-arg to disable PWA / serviceworker (Fixes #232)

[JasperBeaurain]

Description

This PR introduces a build argument to disable the registration of the service worker. Therefore, homer is no longer installed as a progressive web app (PWA) when the build argument was provided during build. That fixes problems when using homer behind an authenticating proxy such as Authalia or oauth2-proxy.

The build argument can be added to the Docker build using docker build --build-arg VUE_APP_DISABLE_PWA=true ..
When the build argument is not provided, Homer is build like normal, inlcuding the PWA.

I propose releasesing two versions of the Docker image: one with PWA & one without PWA. Example: latest & latest-no-pwa.

Fixes #232

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I've read & comply with the contributing guidelines
• I have tested my code for new features & regressions on both mobile & desktop devices, using the latest version of major browsers.
• I have made corresponding changes to the documentation (README.md).
• I've checked my modifications for any breaking changes, especially in the config.yml file

[bastienwirtz]

Hello,

This is no longer necessary thanks to the improvements made on the connectivity checker.

Thanks.