Provide options to disable some of the TypeScript exclusive features

Edited by @aminya

### Background

Just to clarify all the features (autocomplete, data tips, signature help, outline, diagnostics, etc) except a few (Eslint) come from Typescript.
Disabling Typescript means disabling all the features. This the same for all the other IDEs (e.g. VsCode). JavaScript without Typescript almost has no IDE capabilities.

### TODO

With that being said, we can do the following to make the features more customizable:

- Providing an option for disabling the suggestion for installation of the `@types` package. To compensate for the lack of @types, I need to implement a feature that automatically installs @types (e.g. @types/node). This will fix #4 as well.
- Hiding TypeScript version/project/etc from StatusBar making them a unified icon reusable for all the languages. I think a unified status bar icon (which supports all the languages) instead of multiple icons that take space would be more useful.
- Providing a higher priority for personal snippets

ファイル、テスト、エントリポイントは指定されていません。まず、TODO に記載された TypeScript integration と status-bar および snippet handling を追跡します。要求された TypeScript feature controls、自動的な @types のインストール、統一された status-bar icon、personal-snippet priority が、適切なカバレッジとともに実装された時点で作業は完了です。

索引モデルが issue の本文から書いたものです。