Form mounting when completed

[rockwellll]

This PR adjusts the default behavior for mounting forms in a backward compatible way. To not always show the form when it's completed to the user. Forms only mount themselves if they have not yet been completed.

In addition, it's possible to forcefully mount the form regardless if it's been completed or not through passing an object and setting ifCompleted to false, like the following,

hellotext.js/src/models/form.js

Lines 15 to 18 in 74b48c3

	async mount({ ifCompleted = true } = {}) {
	if(ifCompleted && this.hasBeenCompleted) {
	return
	}