Replace the hyperlight git pin with a release #233

#162 pins hyperlight-host and hyperlight-common to hyperlight main (a4563dbd) by git rev, for scratch resize (hyperlight-dev/hyperlight#1947). crates.io refuses git dependencies, so hyperlight-unikraft cannot be published until the pin goes.

Once a hyperlight release includes #1947:

• Bump hyperlight-host and hyperlight-common to that release and drop the [patch.crates-io] sections in Cargo.toml, integrations/clickhouse/Cargo.toml and demos/pptx-gen/Cargo.toml.
• Release v0.21.0 (SNAPSHOT_CONTRACT 8 refuses v0.20.x snapshots).