Fix eslint module resolution errors

[Quaffel]

Fixes eslint module resolution errors that may occur when the project is opened using the provided .code-workspace file.
VS Code should now also prompts users to use the workspace version of TypeScript. This way, it is ensured that the TypeScript language server plugins are loaded as well (including the one responsible for generating proper es module definitions for scss files).

Resolves #6.

List of fixed issues:

• eslint-resolver-webpack-plugin doesn't respect eslint's working directory. Issue has been described here.
• Webpack runs into a similar issue when webpack's resolution mechanism is invoked by eslint (tsconfig.json)
• Workspace's TypeScript version isn't used by default