Remove costly refactorings

[nicoespeon]

This PR removes 2 refactorings:

1. Destructure Object
2. Extract useCallback()

Destructure Object

This one was not working well already (#416). It depended on a POC to resolve the types at runtime, which required the inclusion of the whole "typescript" library in the bundle.

Furthermore, I realized that TS 3.4 introduced a similar refactoring to VS Code: https://devblogs.microsoft.com/typescript/announcing-typescript-3-4/#convert-parameters-to-destructured-object

Extract useCallback()

This refactoring was specific to React. In short, it was applying the auto-fix of the eslint-plugin-react-hooks package.

While this was useful, it's an edge-case that only applies to React codebases. It was not really causing performance issues (although any extra refactoring has a cost), but it required to include many packages in the bundle, including the "typescript" library (used by ESLint and the plugin that was also included).

Impact

The size of the extension bundle went down from ~9MB to ~1.5MB:

Before	After

And for the browser bundle (the one that runs on VS Code Web), it went down from ~5.5MB to ~1.6MB:

Before	After

[nicoespeon]

And somehow it seems that Travis stopped working… We'll see, but eventually, we will move to GitHub Actions (which we already use for deployments), so that would be one less moving part.