Use project monitors to add APM configuration

[ElasticViking]

I plan to use project monitors to add APM configuration (e.g. APM service name) and I want to see the documentation for it to be able to know which options would be available for a configuration such as the one below:

import type { SyntheticsConfig } from '@elastic/synthetics';

export default env => {
  const config: SyntheticsConfig = {
    params: {
      url: 'https://elastic.github.io/synthetics-demo/',
    },
    playwrightOptions: {
      ignoreHTTPSErrors: false,
    },
    /**
     * Configure global monitor settings
     */
    monitor: {
      schedule: 10,
      locations: ['us_west'],
      privateLocations: [''],
    },
  };
  if (env !== 'development') {
    /**
     * Override configuration specific to environment
     * Ex: config.params.url = ""
     */
  }
  return config;
};

Linking as part of the repo: #265