docs: Clean up readme and rename quickstart->encoding example

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ENG-4261 Took 17 minutes

examples/encoding-example/README.md

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+# Encoding example
+
+This guide enables you to:
+
+1. Create a Solution object
+2. Encode the solution to interact with the Ethereum blockchain
+
+## How to run
+
+```bash
+cargo run --release --example encoding-example
+```