docs: add navigation and miner section to README #537

Job	Run time
Test	1m 24s
Clippy	2m 10s
Build	2m 43s
Coverage	1m 40s
Nightly Build & Test	-1s
Docker Nightly Build	-1s
E2E	1m 24s
Integration	1m 25s
Docker Integration (5 Validators + WASM)	39s
Docker	3m 44s
Release	0s
	15m 7s

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