chore: remove the Python SDK

Merged
WI
6d ago
+20-8679

Relaycast SDKs are TypeScript, Rust, and Swift. Publish workflows are npm, crates.io, and SwiftPM.

The unreleased changelog is Patch.

Self-host images and docs install python3 so Node can compile better-sqlite3. Spawn tests use python as an example CLI name for generic process spawn.