automatic style fixes and new workflows

do not require password in session. replaces #135

We do not really care for the password in the session and usually don't
even have it when authenticating via oAuth.

This fixes a warning on PHP 8+

drop concept of GUID and introduce storageID

Previously we created a new GUID for any user trying to login via oauth.
That GUID was used to store the token states. This polluted the cache
area but e

drop concept of GUID and introduce storageID

Previously we created a new GUID for any user trying to login via oauth.
That GUID was used to store the token states. This polluted the cache
area but even worse, it made it impossible to stay logged in on multiple
devices when the IdP invalidated onld access tokens when issuing a new
one (like google does).

Now a session storage is used for the initial login. Permanent storage
is only initialized after a successful login (based on the user's email
address).

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restore proper ID context after login

removed lots of now unused code

another major refactoring

The new OAuthManager is now the main flow manager and should make it
easier to follow the flow. The Session class encapsulates all session
and cookie accesses. A new guid p

another major refactoring

The new OAuthManager is now the main flow manager and should make it
easier to follow the flow. The Session class encapsulates all session
and cookie accesses. A new guid paradigma should make invisible relogins
possible when the session expired. Needs all major cleanup but a first
login worked.

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