log exceptions when listing files
fix amazon s3 issues

folder size and mtime is always unknown in s3

more s3 fixes

make rescanDelay of root dir configurable, add on the fly update of legacy storage ids, !isset -> empty when checking strings

reduce number of http calls on remove and rmdir

fix typo
make some storage tests explain what went wrong
strict comparison
files_extern: remove empty Body and ContentLength in Amazon S3 mount

fixes #10501

Conflicts:
	apps/files_external/lib/amazons3.php
extract batchDelete(), better comments