Add Rosetta Workaround to emulate x86_64 environment for installing CADET-Core on ARM64 architectures to documentation

[hannahlanzrath]

As demonstrated by @talasunna this issue can be bypassed on Apple Silicon Macs by installing CADET-Core (still named cadet on conda) via a Rosetta 2 terminal. Rosetta emulates an x86_64 environment, which allows the Intel-based package from conda-forge to install and run, even though native ARM support is currently missing. This possibility has also been briefly mentioned by our JOSS reviewer before and should be added to the documentation.

Originally posted by @hannahlanzrath in #192