Overview of PR

Add web push notifications functionality in the client as well as in api packages.

All use cases for push notifications (eg. sending notifications when someone joined the system) will be implemented in others pull requests.

How to test

If You would like to test this, follow these steps:

• install deps with yarn
• add test endpoint in push-notifications.controller.ts:

  @Get()
  async send(): Promise<void> {
    await this.pushNotificationsService.send({ title: 'test title', body: 'test body' });
  }

• generate VAPID keys
• add generated private and public keys in api package env file
• add public key in client package env file
• run server with yarn start api package script
• run client with serve:build client script (it requires to be run in production mode)