Enhance cookbook extended filename section
Summary
Move and update the section about extended filename with examples.
Rationale
Extended filename is very interesting features of OTB and not only of OTB-Applications. Therefore put it in a dedicated file which can be extended with new examples seems for me a good idea.
Implementation Details
Classes and files
Add a ExtendedFilenames.rst file and remove this part from the OTB-Applications.rst file
Additional notes
It could be useful for users to have more examples.
