feat: replace find references with custom logic

[kazushisan]

this patch will replace use of ts.LanguageService.findReferences with custom logic

• we should gain a ~2x performance gain (tested with benchmark/excalidraw.sh)
• ts.LanguageService.findReferences was not sufficient enough for our use case. For example it does not report export * from './foo.js'; syntax, dynamic imports, etc. so we had to implement multiple workarounds. This change will streamline the logic and leaves room to implement features like remove unused exports when using import * as syntax #38

[kazushisan]

#41