Javascript package installer version check + lower min node version requirement

[Theodlz]

• lower the min node version required. I don't see why we updated this to 22 (from 20), given that I really don't think we rely on features that 22 has and 20 hasn't. Other than if we have known failures or security reasons, upgrading these things should not be done, so we don't break things for users downstream.
• read the package manager version and not just the package manager name, and have it verified in check_app_environment.py. It looks like with the current version of baselayer, that was ignored