[BUGFIX] Start session when fetching a CSRF token
[BUGFIX] Start session when fetching a CSRF token

This change adds a ``@Flow\Session(autoStart=true)`` annotation to the
method ``Security\Context::getCsrfProtectionToken()``.

Background:

Currently ``CSRF`` tokens are bound to a session. Thus fetching a token
without starting a session makes no sense because the token will be
invalid on the next request.

In the long run we might be able to create "stateless" CSRF tokens that
don't require a session.

Change-Id: Ic7eaf07db4f42f41430effaf7939ce7ca1fd1175
Related: FLOW-130
Releases: master, 2.3, 2.2, 2.1
Depends: I896f6a722445deede1f0a656ea73db04f0d2e978
Original-Commit-Hash: 408919f486ffd78b0f8e38dd00e8e3ddd5601d0d

dlubitz/flow-development-collection,chewbakartik/flow-development-collection,chewbakartik/flow-development-collection,neos/flow-development-collection,aertmann/flow-development-collection,robertlemke/flow-development-collection,aertmann/flow-development-collection,chewbakartik/flow-development-collection,gerhard-boden/flow-development-collection,gerhard-boden/flow-development-collection,dfeyer/flow-development-collection,kitsunet/flow-development-collection,robertlemke/flow-development-collection,kdambekalns/flow-development-collection,albe/flow-development-collection,mkeitsch/flow-development-collection,fcool/flow-development-collection,bwaidelich/flow-development-collection,neos/flow-development-collection,robertlemke/flow-development-collection,daniellienert/flow-development-collection,dfeyer/flow-development-collection,aertmann/flow-development-collection,kitsunet/flow-development-collection,bwaidelich/flow-development-collection,dlubitz/flow-development-collection,albe/flow-development-collection,mkeitsch/flow-development-collection,kdambekalns/flow-development-collection,neos/flow-development-collection,fcool/flow-development-collection,kitsunet/flow-development-collection,dlubitz/flow-development-collection,robertlemke/flow-development-collection,dfeyer/flow-development-collection,mkeitsch/flow-development-collection,kdambekalns/flow-development-collection,dfeyer/flow-development-collection,fcool/flow-development-collection,fcool/flow-development-collection,albe/flow-development-collection,gerhard-boden/flow-development-collection,neos/flow-development-collection,kdambekalns/flow-development-collection,bwaidelich/flow-development-collection,daniellienert/flow-development-collection,daniellienert/flow-development-collection