docs: add FlytePlugins architecture image #1337

Job	Run time
unpack-envvars	1s
Docker Build Images (datacatalog) / build_docker	2m 31s
Docker Build Images (flyteadmin) / build_docker	2m 37s
Docker Build Images (flytecopilot) / build_docker	2m 4s
Docker Build Images (flytepropeller) / build_docker	3m 2s
Build Images / Build & Push Image (datacatalog) / Push to Github Registry	2m 26s
Build Images / Build & Push Image (flyteadmin) / Push to Github Registry	3m 7s
Build Images / Build & Push Image (flytecopilot) / Push to Github Registry	2m 27s
Build Images / Build & Push Image (flytepropeller) / Push to Github Registry	3m 26s
Build Images / Build & Push Image (flytescheduler) / Push to Github Registry	3m 22s
Check Go Generate (datacatalog) / Go Generate	1m 17s
Check Go Generate (flyteadmin) / Go Generate	2m 27s
Check Go Generate (flytepropeller) / Go Generate	2m 24s
Check Go Generate (flytecopilot) / Go Generate	1m 15s
Lint (datacatalog) / Run Lint	2m 23s
Lint (flyteadmin) / Run Lint	3m 30s
Lint (flyteidl) / Run Lint	1m 50s
Lint (flyteplugins) / Run Lint	2m 54s
Lint (flytepropeller) / Run Lint	3m 15s
Lint (flytestdlib) / Run Lint	2m 43s
Unit Tests (datacatalog) / Run Unit Test	2m 52s
Unit Tests (flyteadmin) / Run Unit Test	4m 16s
Unit Tests (flytecopilot) / Run Unit Test	2m 25s
Unit Tests (flyteplugins) / Run Unit Test	3m 46s
Unit Tests (flytepropeller) / Run Unit Test	4m 3s
Unit Tests (flytestdlib) / Run Unit Test	3m 45s
Integration Test (flyteadmin) / Integration tests	5m 49s
	1h 15m 57s

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