fix(core-kernel): boot without .env file

[sebastijankuzner]

Summary

This PR solves #3929

Changes:

1. If .env file is not present program log alert and starts
2. If variable is set in process and in .env, variable from process (system) is taken

Checklist

• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

Merging #3934 into develop will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #3934   +/-   ##
========================================
  Coverage    97.56%   97.56%           
========================================
  Files          629      629           
  Lines        14540    14543    +3     
  Branches      1729     1730    +1     
========================================
+ Hits         14186    14189    +3     
  Misses         165      165           
  Partials       189      189           

Flag	Coverage Δ
#functional	6.82% <0.00%> (-0.01%)	⬇️
#integration	9.85% <0.00%> (-0.01%)	⬇️
#unit	95.72% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
...el/src/bootstrap/app/load-environment-variables.ts	100.00% <100.00%> (ø)
...s/core-kernel/src/services/config/drivers/local.ts	100.00% <100.00%> (ø)

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[faustbrian]

If .env file is not present program log alert and starts was discussed in Slack and I said there we won't allow booting without that file because it contains the defaults for every network.

[sebastijankuzner]

In this case I am closing pull request.