CMake Code Cleaning (part 1)

Summary

Part 1 of #1940 (closed). Simply delete unused code:

• FindGLEW.cmake FindOpenThreads.cmake and use find_package( GLEW )
• FindAgg, FindICUUC, FindKWStyle, FindLTDL, FindMercurial.
• DeployQtConf.cmake, DeployQtConfScript.cmake, Qt.conf.in.
• MinGWPackage.cmake
• UseSWIGLocal.cmake.
• OTB_GENERATE_PROJECT_XML and OTB_GENERATE_SUBPROJECTS_CMAKE in OTBModuleEnablement.cmake.
• CreateTestDriver and CreateTestDriver_SupportBuildInIOFactories in OTBModuleTest.cmake.
• OTB_BUILD_SHARED_LIBS

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
• Optionally, run git diff develop... -U0 --no-color | clang-format-diff.py -p1 -i on latest changes and commit

added refactoring label

If you are in the mood you can also delete UseSWIGLocal.cmake!

PS: I cannot vote anymore but I give you my full support with this champagne bottle emoji!

merged

mentioned in commit 89a974d3

changed milestone to %7.1.0