Create C++ enumerate functions

[jojongx]

We need a C++ template function that features the equivalent of Python's enumerate. This should be placed in mil_tools::itertools.

[andrew-aj]

You could implement something like
this. It allows you to get access to a tuple that you can unpack and refer to the elements with their own variable names like in python.

[jojongx]

Does something of this format need to be added to the CMakeLists.txt?

ament_add_gtest(${PROJECT_NAME}_string_test test/string.cpp)
  target_include_directories(${PROJECT_NAME}_string_test PUBLIC
    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:include>
  )
  target_link_libraries(${PROJECT_NAME}_string_test ${PROJECT_NAME})

I just took this snippet from the file for an example.

I already implemented the enumerate variant from the resource.

[cbrxyz]

You will need to modify CMakeLists.txt in some way, how you modify it will depend on your implementation. You probably will need to add a new ament_add_gtest call for (presumably) your new file!