[BUGFIX] Raise hostname length to 255 characters

When installing TYPO3 in a cloud environment, the 50 character
limit is not high enough. Therefor it is raised to 255 chars,
what most protocols define as the max limit.

Releases: master, 7.6
Resolves: #76132
Change-Id: I59383911e791b635fc80cb6b6b3c76d4433c8e0d
Reviewed-on: https://review.typo3.org/48070


Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Tomita Militaru <militarutomita@gmail.com>
Reviewed-by: Adrian Mot <adrian.mot@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>