Ensure TableInfo only appears in one lib

[dagardner-nv]

• Removes table_info.cpp from morpheus.cmake
• Sets visibility on the TableInfo.as_py_object method, this was showing up as undefined in libmorpheus.so.

I tried just setting #pragma GCC visibility push(default) at the top of the class definition, but this didn't work, according to the gcc docs this is intentional:

In C++, ‘#pragma GCC visibility’ affects only namespace-scope declarations. Class members and template specializations are not affected; if you want to override the visibility for a particular member or instantiation, you must use an attribute.
https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Visibility-Pragmas.html

fixes #271

[drobison00]

Looks reasonable.

[pdmack]

LGTM, no failures from a file smoke test

(morpheus) root@sdk-cli-sdk1:/workspace# nm -C /opt/conda/envs/morpheus/lib/python3.8/site-packages/morpheus/_lib/libmorpheus.so | grep table_info.cpp
(morpheus) root@sdk-cli-sdk1:/workspace# nm -C /opt/conda/envs/morpheus/lib/python3.8/site-packages/morpheus/_lib/libmorpheus_utils.so | grep table_info.cpp
00000000000332f0 t _GLOBAL__sub_I_table_info.cpp

[mdemoret-nv]

LGTM

[mdemoret-nv]

@gpucibot merge