Streamline resource creation api

[Polleps]

Creating new resources with @tomic/lib is currently very unintuitive, to create a resource you need to "fetch" or "get" a resource but tell the store it is new. It also doesn't set any properties so you can't directly save it.

We should have a separate function to create new resources e.g. store.newResource(). Ideally this also takes a class(es) and parent because you have to set those on all resources anyway.

Something like

const resource = store.newResource('https://my-folder', dataBrowser.classes.folder, 'https://my-parent');

Alternatively we could add an overload to the Resource constructor e.g.

const resource = new Resource('https://my-folder', dataBrowser.classes.folder, 'https://my-parent');

Maybe we can add a way to quickly set additional properties too

[joepio]

Some additional thoughts:

• The parent is always required
• A class is not required, but often useful
• A subject could be generated, so it could be an optional argument.

[Polleps]

I just realised we need store to set the parent and a class so going the store.newResource() route makes more sense

[joepio]

That way even the parent becomes optional - we could default to the serverURL.