Implement persistence of addresses manually

[guidocioni]

Even when using persistence the fields of from and to address may not be saved when they're updated by a callback (e.g. when using geolocation, pointing on the map or switching). They only persist user input .

For this reason we need to save the from and to address manually into a json stored locally which is updated every time these addresses change and is loaded at page load time to populate the from and to addresses.

So we need another store component.

We need to do as in point wx

[guidocioni]

Should be implemented in 22296aac1299dc00e8c2179ae4bb7f045b9165e4, although I have the feeling it will stop working at some point