do not share users data with config files

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

Whent trying to upload/rename/create files in a folder that was removed
or rename, the correct error message is now shown.

In the case of upload of multiple files, the upload is cancelled.

This situation can happen if the target folder was renamed or removed
from another browser window or client.

The determineIcon() method was expecting attributes to be set which
caused warnings about undefined indices in the error log.

This fix pre-initializes the array with 'directory' and
'isPreviewAvailable' to make them disappear.

Whenever an exception occurs in the sabre connector code or code called
by it, it will be logged.

This plugin approach is needed because Sabre already catches exceptions
to return them to the client in the XML response, so they don't appear
logged in the web server log.

This will make it much easier to debug syncing issues.

- Refactored download URL building to make it overridable
- Added download URL override in public page
- Added JS unit tests for download URL
- Added OC.redirect() method to facilitate unit testing

Also added dummy table

Added "type=text" makes it look like nice like all other fields

- Upgraded phpseclib to master version (post 0.3.5)
- Now using fopen() on sftp URL for both read and write
- Fixes #4063

add path relative to the files folder of the currently logged in user to the output of getFolderContent()

The cache isn't cleared properly because unlink() doesn't remove the
cache entry which caused side-effects when reusing the same file name
(which randomly happens when time() returns the same value)

This fix first makes sure the unit tests don't fail any more.
The unlink() case with the cache will be investigated separately.

don't use the user id within the versions preview call as it could be used to access previews of another user

OC_Util::setupFS($user) will create a data dir for the given string - no matter if the user really exists - OCP\JSON::checkUserExists($owner); introduces a ready to use check which will bail out with an JSON error

Changed jQuery selector for public preview to public_upload to correctly show preview

The versions and trashbin app are now passing "includeMountPoints=false"
to "getFileInfo()" to make sure that the calculated total size doesn't
include mount points like Shared or external storage.

This is because the default call (legacy) used to return the size of
mount points as well.

Fixes #6731

isPreviewAvailable wasn't always set as the files formatting code is
slightly different than the one from the files app.

Fixes #6423

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