Bundling with Vite 2 - Githubissues

Use vite to bundle source files, so that we can cache them.

Whats in the PR:

no functionality changes
only new dependency is vite
import our old dependencies using npm:
we can split our js code now into multiple files -> better readability
css is bundled into a single file. small images (< 4kB) are inlined into the css file (we import all icons in 'icons.js')
the geojson files are imported in 'base_radlkarte_object.js' and get a hash added to the filename when we build
I have added a vite plugin 'vite-plugin-replace-geojson-in-html.js' that replaces the references to the geojson files in the html file
cache headers are set as follows (using 2 .htacces files): -- html is not cached -- '.json' files in '/data/osm-overpass' are cached for one day -- all other files get a 'version-hash' and are cached for one year
'yarn build' builds the project, 'yarn preview' builds and serves the project, 'yarn serve' serves the project directly from the source (without building)
fixed all lint errors (except one in 'loadGeoJson' -> that one needs a little refactoring, I would do that in another PR)
fixed some spelling and typing errors in index.html

I have added a github action to build and deploy the project

I deploy to https://radlkarte.yxcv.at . You can test the result there
I download the osm-overpass files in course of the deployment. they get no version hash and can be renewed using 'yarn pois'
we can adapt that action to our needs (eg. using a ssh key file instead of userame / password)

TODO: Update the Delopment.md to reflect the changes

markusstraub / radlkarte