[!!!][FEATURE] Remote session management
This introduces the foundations for remote session management – that is,
inspection, modification and destruction of sessions which are not
currently active in the browser running the current HTTP request
This patch also REMOVES the PhpSession implementation and configures
the new, Flow-native implementation to be the default session handler.
If you provided specific configuration for session cookies through
TYPO3:Flow:Session:PhpSession:*, you will need to adjust your settings
to use options in TYPO3:Flow:Session:* instead.
This change set also contains a new type converter which is capable of
converting a session identifier to a session object.