Update app infrastructure

[alexkrechik]

App infrastructure (all the vs code libs, running scripts, etc.) should be updated.

[alexkrechik]

There are a lot of problems with the current setup:

1. The final build file is not optimized
2. Complicated to run extension locally
3. All the vscode-related libs are outdated.
4. typescript and other helper libs are totally outdated as well.

[alexkrechik]

I will do the final review, but https://github.com/alexkrechik/VSCucumberAutoComplete/pull/484/files works locally. Main updates:

1. Updated all the VsCode libraries to the latest versions
2. Updated Typescript to the latest version and fixed all the typings
3. Moved to Jest usage instead of old versions of Chai + Mocka
4. Simplified work with a project opened in one folder - moved almost all the required functional to the root package.json

[alexkrechik]

This issue is to be fixed or implemented in the 3.0.0 version of the extension. If this issue is unresolved or there are additional notes, please create a new ticket with the necessary details.