perf: decrease package size

[Lehoczky]

Closes #262

I've checked locally, the package still works without the source folder and the tsconfig file.

Package size before:

After:

[Shinigami92]

We can only do that, if we turn on sourcemaps 🤔
The src files are there to make debugging easier

[Lehoczky]

Looking into that 👍 🧐