Allow opening GenBank files with annotations joined on different strands

GenBank files can contain joined annotations with regions, located on different strands. UGENE can't open such files now, because the annotations model doesn't allow storing such annotations.

Improve the GenBank format support as follows: such files must me opened in UGENE with a warning message with the report:

There were some problems when opening the 'file_name.gb' file.

The file contains joined annotations with regions, located on different strands. All such joined parts will be stored on the same strand!

The opened file must be marked as modified in the Project View. If the user will close the file without saving the modification, the file must be the same. This is important as the file open-save-open scenario will still work incorrectly in this case.