docs: architecture documentation

[RomainMuller]

Adds a document outlining what orchestrion does during execution.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

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Additional details and impacted files

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  Coverage        ?   73.34%           
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  Files           ?      104           
  Lines           ?     5402           
  Branches        ?        0           
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  Hits            ?     3962           
  Misses          ?      959           
  Partials        ?      481           

Components	Coverage Δ
Generators	83.23% <ø> (?)
Instruments	∅ <ø> (?)
Go Driver	78.29% <ø> (?)
Toolexec Driver	73.62% <ø> (?)
Aspects	79.05% <ø> (?)
Injector	78.26% <ø> (?)
Job Server	73.91% <ø> (?)
Integration Test Suite	∅ <ø> (?)
Other	73.34% <ø> (?)