make sure that we don't find the wrong shares if a user and a group have the same ID

Fix type hinting for app manager

Check if the size field is available

make sure that we only find the shares from the correct share type if users and groups with the same ID exists

Remove unused code

Make declaration compatible

Add tests for normalizePath() with absolute paths on windows

Fix remote.php routes for apps that are enabled for specific groups

In some cases the 'size' field is not available resulting in some PHP errors such as:

```json
{"reqId":"03548fd9e3d3aca15a5796b3b35d7b9d","remoteAddr":"::1","app":"PHP","message":"Undefined index: size at \/Users\/lreschke\/Programming\/core\/lib\/private\/files\/fileinfo.php#125","level":3,"time":"2014-11-17T21:38:57+00:00"}
```

This can be experienced when creating a new empty file and deleting it right away, then when going to the trash bin this error is thrown.

Move CSRF check

Fixes #12236

delete all children's previews when deleting a folder

Issue/10991 Make unit tests pass on windows

Add \OC\App\Manager to handle enabling/disabling apps

Because we're closing the session now before controllers are executed there are cases where we cannot write the session.

We don't support direct updates from older ownCloud versions except the previous one therefore this code is unused and can be removed.

eliminate OC_Template::printErrorPage in database classes, fixes #12182

Check if app is enabled for user

Fixes https://github.com/owncloud/core/issues/12188 for AppFramework apps

Fix share download