[C++][Pistache] Add support for validating arrays, use full namespace type with custom types

[muttleyxd]

fixes #11246

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@ravinikam (2017/07) @stkrwork (2017/07) @etherealjoy (2018/02) @MartinDelille (2018/03)

[muttleyxd]

@ravinikam (2017/07) @stkrwork (2017/07) @etherealjoy (2018/02) @MartinDelille (2018/03)

anyone?

[wing328]

Tested locally and the result is good:

/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[ 84%] Building CXX object CMakeFiles/api-server.dir/model/Inline_object_1.cpp.o
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[ 87%] Building CXX object CMakeFiles/api-server.dir/model/Order.cpp.o
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[ 90%] Building CXX object CMakeFiles/api-server.dir/model/Pet.cpp.o
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[ 93%] Building CXX object CMakeFiles/api-server.dir/model/Tag.cpp.o
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[ 96%] Building CXX object CMakeFiles/api-server.dir/model/User.cpp.o
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[100%] Linking CXX executable api-server
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)
[100%] Built target api-server
/usr/bin/cmake: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/cmake)

Thanks for the PR 👍