[TASK] Remove hash_base from page cache data

The hash_base (the array from which the cache hash is calculated) is
saved into the cache. But this information isn't required. Also it isn't
processed after read from cache. So this data gets removed to save
bandwidth and to reduce the string to be unserialized.

Resolves: #53404
Releases: 6.2
Change-Id: I76411a9d89e483fed1b29573359b001fa921b244
Reviewed-on: https://review.typo3.org/25191
Reviewed-by: Mathias Schreiber
Tested-by: Mathias Schreiber
Reviewed-by: Markus Klein
Tested-by: Markus Klein