Remove more c_str with itk::ExceptionObject string constructor

Summary

• Forward std::string constructor in OTB exception classes derived from itk::ExceptionObject
• Remove 26 calls to c_str now not needed when throwing those exceptions

Rationale

#513 (closed)

Copyright

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

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Check before merging:

• All discussions are resolved
• At least 2 votes from core developers, no vote.
• The feature branch is (reasonably) up-to-date with the base branch
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• Copyright owner has signed the ORFEO ToolBox Contributor License Agreement