Create conan packages for different versions of Python

[gagelarsen]

Feature Request: Currently we only build for Python version 3.6.8. We should expand that to work with version 3.7, 3.8 and 3.9, as well as make it easier to expand that when different version of python are released.

Expected Work:

1. Change pybind option to be a string instead of a bool. Probably something like (None, 3.6.8, 3.7, 3.8, 3.9)
2. Create new conan dockers for the build process for linux builds.
3. Update the CMakeLists.txt to be more consistant and use the new pybind string option.
4. Update build.py to filter out any builds we don't want from the side effect of adding the new versions of python.
5. Update the upload_python_package function in the conanfile to let aquapi know which version of python this is for.

Things that Came up...

• Ubuntu no longer supports GCC5 so we dropped support and added GCC8.

[gagelarsen]

After researching making the new dockers, i found that the latest ubuntu doesn't play well with GCC5. We decided since it wasn't widely used anyways we would drop support for GCC5. We also decided to add support for GCC8