feat: ES module compatibility

[ecarriou]

What has been done

• System Runtime is now an ES module. You can now use the JavaScript native import API to import the library from a CDN:

<script type="module">
  import runtime from 'https://cdn.jsdelivr.net/npm/system-runtime@6.0.0-beta.5/dist/system-runtime.js'
  const system = runtime.system('mySystem')
  // ...
</script>

• You can now use the JavaScript native import API to import the library in nodeJS:

  import runtime from 'system-runtime'  
  const system = runtime.system('mySystem')
  // ...

• Breaking change: we can not use require in the code. We have this breaking change because your scripts are evaluated inside System Runtime which is now an ES module.
• Breaking change: we change the way we access collections with $db internal component. Example:

// before
$db.Person.find()

// now
$db.collections.Person.find()

• We can now use dynamic import for event:

Person.on('anEvent', async (val) => {
  const newValue = await import('../address.js')
  this.address(newValue.default)
})

• Added Mocha and Cypress for server and frontend tests.
• Added Rollup for building the frontend package / source map.
• Improved DX: use of prettier, eslint, format/check on commit.

How to test the PR

Test in HTML

• install the lib in your HTML:

<script type="module">
  import runtime from 'https://cdn.jsdelivr.net/npm/system-runtime@6.0.0-beta.5/dist/system-runtime.js'
</script>

• play with the library:

<script type="module">
  import runtime from 'https://cdn.jsdelivr.net/npm/system-runtime@6.0.0-beta.5/dist/system-runtime.js'
  console.log(runtime.version())
</script>

Test with nodeJS

• create a JavaScript project that is ES compliant (i.e. with "type":"module" in the package.json),
• Install the lib with npm i system-runtime@6.0.0-beta.5.

You will have something like that in your package.json:

{
  "type":"module",
  "dependencies": {
    "system-runtime": "^6.0.0-beta.5"
  }
}

• Create a JavaScript file and import system-runtime library:

import runtime from 'system-runtime'

• play with the library:

console.log(runtime.version())

TODO

• [x] remove call to require API to load system.
• [x] clean system.
• [ ] tests with System Designer.