check memory requirement in contactmap

[rvhonorato]

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Checklist

• Tests added for the new code
• Documentation added for the code changes
• Modifications / enhancements are reflected on the haddock3 user-manual
• CHANGELOG.md is updated to incorporate new changes
• Does not break licensing
• Does not add any dependencies, if it does please add a thorough explanation

Summary of the Pull Request

This PR adds a logic to check if the host machine has the necessary memory requirements to run contactmap and if it does not it skips the execution of the module.

⚠️ IMPORTANT ⚠️

To get the available memory of the system we are now using psutil, this means this is now a dependency of the project! https://pypi.org/project/psutil/ is a very stable and mature package and is the best way for us to get the available memory in different systems.

Related Issue

#1499

Additional Info

for prosperity: I tried to bypass calculating the matrix and adding a generation with on-the-fly calculation of the contacts, as this would avoid keeping things in memory. However changing this also needs a significant refactoring - basically a whole re-write of this module.