MR !6

This is a major change to the architecture of Operations 1, a new version is warrented.
- Brand new UI: Site teasers show all information in easy to read display.
- Create Site Entities from ANY URL. Add google.com or drupal.org.
- Site Manager homepage: List of site teasers.
- Views support.
- Better UX for setting up site.module: Add drupal site, if no SiteAPI is found, instructions appear.
- Checks HTTP status on all URLs.
- Extract fields from headers and content where possible, such as PHP Version, Drupal version, Site Title and Host provider.
- Site Type bundle: Website, Drupal Website, Site Manager.
- Bundle classes with inheritance: DrupalSiteBundle extends PHPSiteBundle extends SiteBundle.
- `SiteProperty` plugins can now define the bundle classes they are attached to, making it easy to attach property fields to multiple Site Types.
- Add Site Manager sites to send data to multiple Site Managers.
- `SiteEntity` is now for any website.
- `DrupalSite` entity is now the entity with Drupal Site UUID as ID. `SiteEntity::drupal_site` field is a reference to `DrupalSite` DrupalSite entities get created automatically. DrupalSite entity page shows all sites for that Drupalsite.
- Removed SiteDefinition config entity.
- More automated behat tests.
- New `SiteAction` plugin with first implementation: User Login. Remotely log into a site!
  - SiteActions create a new link in the "Operations" dropdowns, and work locally or remotely. See `SiteActionsBasePlugin`.
- New Properties:
  - HTTP Status, generated from list of SiteURLs.
  - Site Title, generated from HTML title.
  - Drupal Site Name.
  - Last Cron run.
  - Site Installation time.
  - Site Install profile.
- FieldFormatter widget for State & Reasons.
- JSON:API. Site Module now uses JSON:API for posting and getting data. 
- Added "ox_stock" install profile for basic site manager install.