change build system to esbuild and add rdflib.js

[neon12345]

A possible starting point for future development.

[BlackDark]

Hi @neon12345, things probably break now a lot (tests, and local server starting not working i guess).
For a good future development we need to get those also running.

IMO we need to also get rid of all the legacy structure the whole projects consists. Its all legacy code from the early stages of javascript.

[neon12345]

@BlackDark I plan to remove the server and add client-side parse and export with rdflib.js. The tests need to be done differently but the project builds and runs with esbuild. I test it with python3 -m http.server in the deploy folder and it does what I need for now.

[neon12345]

I have now added browser-based automated testing with 4 working examples. If the parser is complete with more examples, it can be integrated into the web app.

[BlackDark]

I have now added browser-based automated testing with 4 working examples. If the parser is complete with more examples, it can be integrated into the web app.

Allright, give me a ping once ready with all.