Update `form` with new component registration logic & update input to latest version

[chrisfalaska]

Update the form component to use the new component registration logic (example: https://github.com/AlaskaAirlines/auro-icon/issues/144)

• How will children components also take advantage of the custom registry (ie, input, dropdown, etc)?

Issues raised

• [ ] Update form with new registration logic
• [ ] Update input/demo/api.html
• [ ] Update input/demo/index.html

[sun-mota]

There is a dup: #13

[sun-mota]

blocked by

• [ ] #16
• [ ] https://github.com/AlaskaAirlines/auro-input/pull/346
• [ ] https://github.com/AlaskaAirlines/auro-input/pull/357