Upgrade Catch framework to to Catch2

[UgiR]

Currently, Catch is installed via apt-get. Unfortunately, this means the Catch version being used is v1.1.

In order to use Catch2, the up-to-date Catch header needs to be included with the autograder.

Because of the memory limitations of the autograder container, it is unable to compile the Catch2 header. This can be resolved by choosing higher specifications for the autograder in the Gradescope settings. Ideally, this autograder should be self-contained and run 'out of the box', without any need to change additional settings (unless so desired).

In order to accomplish this, swap space can instead be increased to meet the memory requirements of the compiler. Since the compilation of the Catch header seems to be the only bottleneck, this should be sufficient.

[UgiR]

Update: Since the autograder is running in a Docker container, attempting to create a swapfile results in 'operation not permitted.'