testRewind tests reading and writing after rewind on an encrypted stream; testWriteWriteRead tests r+ mode

When moving back the pointer to position 0 (using stream_seek), the pointer on the encrypted stream will be moved to the position immediately after the header. Reading the header again (invoked by stream_read) will cause an error, writing the header again (invoked by stream_write) will corrupt the file. Reading/writing the header should therefore happen when opening the file rather than upon read or write. Note that a side-effect of this PR is that empty files will still get an encryption header; I think that is OK, but it is different from how it was originally implemented.

[encryption] fix moving files to a shared folder

Ignore test folders when checking the code for compliance

Tear down FS after running trash expire

Show hint if there is no delete permission

Add missing loading indicator for enabled apps

Issue 15804 occ user delete exception

* add class .no-permission which shows the default delete icon
* fixes #15172
* add unit test for no permission and for delete permission

* happened when an app gets activated, because the
  new appended HTML doesn't contain the loading
  image
* fixes #15806

Fix webdav access for public reshare

update icewind/smb to 1.0.1

Delete temp files after testing encryption stream wrapper

Checks if getenv returns proper system environment variable results

Only get encryption status when logged in

This removes useless warnings in the logs.

Updated texts and changed the variable name to match the query

Updated text + info which path for php config is used

removed the term ownCloud and squashed the commits

Updated text

Reset sharedialog values