MH-10109, Let Extracted Text Pass Through Unmodigied

The TextExtractor would already do some filtering on extracted texts.
This was unnecessary as later on, it is done by the DictionaryService
anyway and would even cause trouble as in some cases special characters
were removed as well.

This commit will just remove the filtering from the extractor.

Signed-off-by: Lars Kiesow <lkiesow@uos.de>

Conflicts:
	modules/matterhorn-textextractor-tesseract/src/test/java/org/opencastproject/analysis/text/TesseractTextFrameTest.java