The write-hook also is triggered for created files

Fix #8131

That method was moved to the external storage recently so
isn't needed here any more.

When using an external cache folder, it is automatically mounted in
FileSystem::initFileSystem so that any app can use it transparently
by creating a view on the "/$user/cache" directory.

Moved the mounting code for external storage from
OC\Filesystem::initMountPoint to files_external using the
post_initMountPoints hook

This patch was automatically generated as part of the following inspection:
https://scrutinizer-ci.com/g/owncloud/core/inspections/cdfecc4e-a37e-4233-8025-f0d7252a8720

Enabled analysis tools:
 - PHP Analyzer
 - JSHint
 - PHP Copy/Paste Detector
 - PHP PDepend

do not share users data with config files

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>

Added argument to getFileInfo() to disable adding the size of
mountpoints to a directory's size.

Fixes #5924

Now removing "/./" and trailing "/." from the paths when normalizing.

Legacy home storage ids with the format "local://path/to/datadir/user1"
are now also wrapped by the HomeStorage.

Conflicts:
	lib/private/vcategories.php

This reverts commit 079f918d.

this is needed because there is no possibility to set $defaultInstance to false after filesystem::init

revert changes to fbbc76f2 because master is very unstable right now