POD NOTES: Migrate to solidpod:SolidLogin()

[gjwgit]

Description

The PodNotes app has an implementation of the login screen to connect to the Solid Pod and initialise the Pod if required. This is now implemented in the solidpod package.

This task is to migrate the Solid Pod login and Pod initialisation to using SolidLogin() from the solidpod package.

Why

So that we test the SolidLogin() functionality and migrate the app to be a template for app developers.

[gjwgit]

We might put this on hold for now. Once we have demonstrated end-to-end using KeyPod then migrate PodNotes to using solidpod.

[gjwgit]

This is ready to go now. We can login, and read and write data through solidpod. Currently we can not manage permissions.