[TASK] EXT:sysext: enlarge column field in sys_refindex to 64 chars

Concern extension "sysext".

Additional field names in the database tables, which are greater than
40 characters are not completely saved. Often new columns have an
extension prefix and a name.
e.g. tx_myextension_model_tags_customFieldName
Since MySQL 5.5+ it is possible to define database table name
columns with 64 characters.

The fix is for the master branch and backporting the version 7.6 LTS.
Version 7.6 LTS requires MySQL version 5.5+.

Resolves: #77323
Releases: master, 7.6
Change-Id: Ia163599c37c53275b0e36443f4f9f4c52919800a
Reviewed-on: https://review.typo3.org/49371


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>