Apply main eslintrc rules only onto typescript files

[stijnklomp]

Only apply the main rules to Typescript files:

overrides: [
    {
        files: [".ts"],
                parser: "@typescript-eslint/parser",
        parserOptions: {
            project: "./tsconfig.json",
            sourceType: "module",
            tsconfigRootDir: __dirname,
        },
        rules: {
                    ...
        }
    }
]