[BUGFIX] Limit maximum key length on sys_refindex

Prevents issues if key length exceeds maximum key
lengt for the SQL server. Keys are now kept below a
255 byte limit.

Change-Id: I8e0c2a167f94695dd728c777368fac9e779678d8
Resolves: #79993
Releases: master
Reviewed-on: https://review.typo3.org/51828


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Thomas Hohn <thomas@hohn.dk>
Tested-by: Thomas Hohn <thomas@hohn.dk>
Reviewed-by: Anders Kostending <aha@systime.dk>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>