Remove dotenv dependency

[TheZoker]

Fixes #266

[sdirix]

I had a look at this with @lucas-koehler and he brought up a valid statement:

We should just generate a source file with the current version and import this like any other file in the sources. Thereby the version would always be available and there is no need to dynamically fetch it.

Can you adapt the PR accordingly?

[TheZoker]

Thanks for the review!
I adapted the logic accordingly.
I also created a default version file, so even without running the ./build.sh script, the app does start without throwing an error.

If you want to place the version file into another directory, please let me know. Also if you want to use other default version, let me know. Thanks!

[lucas-koehler]

Hi @TheZoker , thanks for the update! LGTM now ✨

[lucas-koehler]

@TheZoker please rebase the changes onto main. I'll merge and squash then.

[lucas-koehler]

LGTM! Thanks for the quick updates :)