Hello World

[isedwards]

Create a robust deployable preact PWA that initially doesn't do anything, but should include: (https://developers.google.com/web/tools/lighthouse/)

• [ ] Initial test suite with documentation on how to run tests - is 100% test coverage possible
• [ ] Add a test coverage shield to opencdms-app/README.md (using coverall.io?)
• [ ] Installable as app option with offline message (could be moved to a later issue)
• [ ] Be aware that the user can select the CSS theme used for the app (#3) - themes may use different libraries, e.g. bootstrap (see later issue)
• [ ] Document how to check the [lighthouse score]
• [ ] Document use of SCSS, TypeScript and build process