feat: memcheck with tests

[XavierChanth]

- What I did

• Added a Dockerfile to build a memcheck environment that can be run locally
  • Neither valgrind or valgrind-macos are supported on apple silicon, hence the need for docker
• Added three main just commands:
  • just memcheck
    • run memcheck without the docker container, suitable for machines which are configured to run ctest memcheck
  • just setup-memcheck-docker
    • calls docker build with the appropriate arguments
  • just memcheck-docker or just memd (alias)
    • Runs the ctest -T memcheck ... in a temporary docker container
    • The build & test logs are cached on disk, meaning re-runs don't require a full rebuild
• There are some discovered leaks which need to be resolved before we add this to CI

- How I did it

- How to verify it

Local run:
https://gist.github.com/XavierChanth/7051e076e9e03cdf1444c6484c69a386

- Description for the changelog
feat: memcheck with tests