Non-GPUE dependencies included in repo

[mlxd]

Hi all, I have noticed some external source files included from other repositories in some of the branches. I would appreciate it if these were not checked-in, and only pulled down during the initial clone/build step.

While licensing may be compatible, it is an area that can cause headaches later, and so not including these deps here would be preferred.

I am currently working on the CMake build, of which many of these deps can be pulled in as required when fully set up. I would like these deps to be scrubbed from the history as well when completed (e.g. catch2, etc.). Thanks.