[LMS-2585] implemented: write a generic dropbox to import Opera Flex files

...e/java/ch/systemsx/cisd/common/geometry/SpatialPoint.java

.../ch/systemsx/cisd/imagereaders/bioformats/FlexHelper.java

...systemsx/cisd/imagereaders/bioformats/FlexHelperTest.java

...urceTest/resources/images/bioformats/valid/001001000.flex

...urceTest/resources/images/bioformats/valid/032045000.flex

...mple-dropbox-configuration/opera-flex/data-set-handler.py

.../ch/systemsx/cisd/openbis/dss/etl/TileGeometryOracle.java

...sd/openbis/dss/etl/biozentrum/ImageMetadataExtractor.java

...systemsx/cisd/openbis/dss/etl/TileGeometryOracleTest.java

...penbis/dss/etl/biozentrum/ImageMetadataExtractorTest.java