docs: Add Argo CD components architecture doc

[leoluz]

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[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.03 ⚠️

Comparison is base (9b53eeb) 49.05% compared to head (dd0a42e) 49.02%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #13194      +/-   ##
==========================================
- Coverage   49.05%   49.02%   -0.03%     
==========================================
  Files         246      247       +1     
  Lines       42569    42692     +123     
==========================================
+ Hits        20882    20931      +49     
- Misses      19572    19645      +73     
- Partials     2115     2116       +1     

see 10 files with indirect coverage changes

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[cjc7373]

Is it reasonable that this doc can be merged with operator-manual/architecture?