implement basic encryption functionallity in core to enable multiple encryption modules

.gitignore

apps/encryption_dummy/appinfo/app.php

apps/encryption_dummy/appinfo/info.xml

apps/encryption_dummy/appinfo/version

apps/encryption_dummy/lib/dummymodule.php

lib/base.php

...ryption/exceptions/encryptionheaderkeyexistsexception.php

...te/encryption/exceptions/modulealreadyexistsexception.php

...te/encryption/exceptions/moduledoesnotexistsexception.php

lib/private/encryption/keys/factory.php

lib/private/encryption/keys/storage.php

lib/private/encryption/manager.php

lib/private/encryption/update.php

lib/private/encryption/util.php

lib/private/files/fileinfo.php

lib/private/files/storage/wrapper/encryption.php

lib/private/files/stream/encryption.php

lib/private/server.php

lib/public/encryption/iencryptionmodule.php

lib/public/encryption/imanager.php