Generate a `versions.toml` with the SDK (#1311)

* Implement `crate-hasher` utility to hash crate source files
* Add `generate-version-manifest` subcommand to publisher tool
* Incorporate `generate-version-manifest` into the build system
* Start making the PR bot run through the Docker build image
* Use nightly clippy in tools CI when necessary
* Fix transient failure when acquiring the build image
* Include examples repo revision in `versions.toml`
* Fix nightly clippy lint in `cargo-api-linter`
* Track examples revision in sync tool
* Make it easier to run Docker CI locally