Allow retrieving multiple components

[RubenVerborgh]

Currently, instantiateFromUrl allows specifying one componentUrl.
It would be interesting to specify an array and get back a key/value object.

[RubenVerborgh]

Implementation suggestion: it basically comes down to instantiating a Record<string, any> object; if needed, a dummy class could do:

class DummyRecord {
  constructor (record: Record<string, any>) {
    return record;
  }
}