Store intermediary result into a separate and dedicated directory

Intermediary results are computed and stored in the input directory within the .SAFE structure.

This pollution makes testing more complex and may have other side effects to users expecting a stability in their SAFE directory.

Note: Past versions of OTB Orthorectification required the whole SAFE structure to run. We need to check whether the metadata within the accompanying geom file is enough. If not, We may have to replicate the SAFE structure into the temporary directory with hard or symbolic links.