ci: add devcointainer

[nicky-ru]

What does this PR do?

• adds devcontainer config
• adds Dockerfile.dev

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 50.87%. Comparing base (ce2ed7b) to head (e2b30c2).

❌ Your project status has failed because the head coverage (50.87%) is below the target coverage (70.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #121   +/-   ##
=======================================
  Coverage   50.87%   50.87%           
=======================================
  Files         180      180           
  Lines       24441    24441           
  Branches     2251     2251           
=======================================
  Hits        12435    12435           
  Misses      11962    11962           
  Partials       44       44           

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