guide user through initial setup

[angelo-v]

As a new WebClip user without Solid know how
I want to be guided step by step through the intial setup
So that I can understand how to get a pod and use it with webclip

As a Solid user on NSS who discovered WebClip
I want to allow WebClip to write to my Pod
but I do not know or care about the differences between chrome-extension:// and chromiumapp.org origins

[angelo-v]

Open tasks:

• only show relevant section / next step
• loading indicator while checking access permissions
• only ask for authorization on pods that use trusted apps
• close authorization page and go back to options page automatically
• clean up package structure and dependency graph regarding common modules like api
• refresh infos on option page after successfull authorization / pod connection
• handle login errors
• fix dev mode for options page