[BUGFIX] Change localconf.php to LocalConfiguration.php

Change localconf.php to LocalConfiguration.php in the text
How to configure TYPO3 from InstallTool

Resolves: #43425
Releases: 6.1, 6.0

Change-Id: Iebd49647ec7657162fd92cc194ba5463109f61dc
Reviewed-on: https://review.typo3.org/17281
Reviewed-by: Mattias Nilsson
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter