fix(cli): don't hardcode the minimum required Node version

[malept]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Also has a little refactor and adds a warning message.

[codecov]

Codecov Report

Merging #2003 into master will decrease coverage by 0.04%.
The diff coverage is 63.63%.

@@            Coverage Diff             @@
##           master    #2003      +/-   ##
==========================================
- Coverage   72.69%   72.65%   -0.05%     
==========================================
  Files          74       74              
  Lines        2216     2220       +4     
  Branches      419      420       +1     
==========================================
+ Hits         1611     1613       +2     
- Misses        443      444       +1     
- Partials      162      163       +1     

Impacted Files	Coverage Δ
packages/api/cli/src/util/check-system.ts	71.42% <63.63%> (-2.26%)	⬇️

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