Migrate file parsing code to wellen library

[Lramseyer]

This could possibly solve the 2GB limit issue AND add support FST and GHW files.

The wellen library is a parser for waveform dump file formats, written in rust. I would need to update the build flow to add the rust to webassembly compilation step and build out a Typescript interface to interact with it all, as the rest of the extension is written in Typescript.

I do not know how to do this, so help in any way would be much appreciated!