docs: replace TODO placeholders with API and SDK overview description… #17

Job	Run time
opentelemetry-opencensus-shim	21s
opentelemetry-getting-started	32s
opentelemetry-proto-gen-latest	17s
opentelemetry-protojson-gen-latest	23s
opentelemetry-exporter-opencensus	20s
opentelemetry-exporter-zipkin-json	18s
opentelemetry-exporter-otlp-proto-grpc-latest	27s
opentelemetry-exporter-otlp-combined	21s
opentelemetry-api	26s
opentelemetry-codegen-json	24s
opentelemetry-propagator-b3	25s
opentelemetry-exporter-otlp-proto-http	23s
opentelemetry-opentracing-shim	25s
opentelemetry-sdk	26s
opentelemetry-exporter-prometheus	26s
opentelemetry-exporter-otlp-proto-common	21s
opentelemetry-exporter-zipkin-proto-http	19s
opentelemetry-propagator-jaeger	25s
opentelemetry-exporter-zipkin-combined	19s
opentelemetry-test-utils	18s
opentelemetry-semantic-conventions	25s
	8m 1s

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