ENH: Improve errors messages when loading app fail

Improve errors messages when loading app fail

Summary

Display a more precise reason why an OTB application could be not loaded.

Rationale

When we try to load an OTB application and when this fails, the error message assumes that we have given an incorrect application name.

Sometimes this is simply not the case: the dynamic library may be missing symbols, it may need other dynamic libraries not in the $LD_LIBRARY_PATH...

Of course, we could set LD_DEBUG=libs on many *nix boxes -- if we are aware of its existence, when we have given up on other leads, when we are on a *nix box...

Fortunately ITK provides the information in a portable manner, so let's cut the chase and simply give it to the end-user.

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
• Dashboard is green
• Copyright owner has signed the ORFEO ToolBox Contributor License Agreement