Option to create a full backup about microstream

[hg-ms]

Tested the StorageBackupHelper class:
Using this class allows to create full backups. This helper class is working but i would suggest it move its functionality into the StorgeManager for easy usage. Currently the StorageBackupHelper forces the user to keep an explicit reference to the StorageFoundation tio initialize the StorageBackupHelper.

The export of the channels data files is already available in the StorageManager (see one.microstream.storage.types.StorageConnection.exportChannels(StorageIoHandler, boolean))

The export of the type dictionary is currently not available from the StorageManager but may be added quite easy. Maybe the existing PersistenceTypeDictionaryExporter can be utilized.

[tm-ms]

CK has stressed that having such a feature in the public API would be very helpful.

[fh-ms]

Added issueFullBackup methods in StorageConnection (EmbeddedStorageManager).

[zdenek-jonas]

ok, works.