[TASK] Remove unnecessary usage of the encryption key

The encryption key should not be used within a single hash function,
but only by using hmac if needed.
For cache busting, using the encryption key is not needed at all
so we remove it.

Releases: master
Resolves: #68365
Related: #68133
Change-Id: I5c87008f0b733dab2c13fbc224f0ff6fd5e4b199
Reviewed-on: http://review.typo3.org/41701


Reviewed-by: Sebastian Michaelsen <michaelsen@t3seo.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>