Use Prettier and ESLint

[grant]

Use standard Google prettier and ESLint as used in the Node client library:
https://github.com/googleapis/google-api-nodejs-client

---

Example:

.prettierrc.js

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

module.exports = {
  ...require('gts/.prettierrc.json')
}

---

.eslintrc.json

{
  "extends": "./node_modules/gts",
  "rules": {
    "quotes": [2, "single", "avoid-escape"]
  }
}

---

.eslintignore

**/node_modules
**/coverage
test/fixtures
build/
docs/
protos/
src/apis