Remove obsolete metadata_processor and visualization services

[cchwala]

• Delete metadata_processor (superseded by parser service)
• Delete visualization (superseded by Grafana integration in webserver)
• Update docker-compose.yml to remove both service definitions
• Update README.md with accurate service descriptions
• Document processor service as stub implementation
• Clarify actual data flow through parser service

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.64%. Comparing base (2ec65bf) to head (b3b0669).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #15   +/-   ##
=======================================
  Coverage   64.64%   64.64%           
=======================================
  Files          19       19           
  Lines        1547     1547           
=======================================
  Hits         1000     1000           
  Misses        547      547           

Flag	Coverage Δ
mno_simulator	85.82% <ø> (ø)
parser	78.35% <ø> (ø)
webserver	29.63% <ø> (ø)

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