Automate release processes with release-plz

[ianthetechie]

• Add release-plz automation as in chore: automate release process pmtiles-rs#66
• Create a RELEASE_PLZ_TOKEN
• Figure out how to do our funky ordered release (we need to release crates in a specific order)

Originally posted by @nyurik in #22 (review)

[nyurik]

ordering is usually done automatically. Take a look at https://github.com/varnish-rs/varnish-rs/blob/main/release-plz.toml -- 3 crates with the same version get auto-bumped and released together