Parse glossary bib files to populate intellisense

[jlelong]

Close #4472

This PR implements the use of glossary .bib to populate intellisense.
As glossary intellisense treats glossary and acronym entries differently, we do the same when parsing .bib files. Currently only @entry entries are considered as glossary entries. Everything else is considered as an acronym entry.

Hopefully I will manage to add some automatic tests but some more intensive testing from people who actually use bib2gls is more than welcome. @LeoJhonSong Could we count on your feedback?

@James-Yu A lot of the newly added code looks very similar to the one used in completion/completer/citation.ts. Yet, factorizing both is not so obvious and would require to extract sub functions. I will think of it but feel free to share your thoughts if any.

Btw Merry Christmas @James-Yu

[LeoJhonSong]

@jlelong Sure, I got your back! Thank really much for the commit in Christmas haha 😄

I can catch up with updated extention once released and test it out. Also, I can provide three .bib files I used if helpful. Please feel free to let me know if there is anything else I can help.

BTW as an glossaries-extra user, from my point of view, "everything else from @entry" could be better described by abbreviation, but not acronym.

[James-Yu]

Merry Chrismas @jlelong @LeoJhonSong and everyone!

Yeah the implementation looks quite good to me. I think it's fine to duplicate these functions, who knows if they may diverge or not later. Feel free to merge when you think good!