Correctly take into account the extended filename writerpctag

Summary

The extended filename writerpctag was not taken into account. With this MR, the output image will contain the RPC model if writerpctag=true even if the proejction is present.

Rationale

Fix #2295 (closed)

Implementation Details

Classes and files

• Modules/IO/IOGDAL/include/otbGDALImageIO.h: New class function GDALMetadataWriteRPC
• Modules/IO/IOGDAL/src/otbGDALImageIO.cxx: Call GDALMetadataWriteRPC when writerpctag=true

Copyright

The copyright owner is CNES and has signed the ORFEO ToolBox Contributor License Agreement.

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