Checks and Tools for the new release process

[ggwpez]

As #2490 is shaping up, now we can collect things that we will need for its implementation (please extend):

Tasks

Beta Give feedback

1. [CI] Prevent breaking changes in minor/patch bumps #3292
   +0
2. [CI] Prevent multiple version bumps of the same crate on master since the last stable release
3. [CI] Testing back-portability (whether a non-breaking change can be applied clean to stable and tests work)
4. Tool to figure out correct nightly and stable versions when bumping versions, tracked in [meta] v0.1 Features liamaharon/cargo-workspace-version-tools#1
5. Tool for clobbering, tracked [meta] v0.1 Features liamaharon/cargo-workspace-version-tools#1
6. Do a one-off sync with the versions of crates-io: Sync Cargo.toml and crates.io versions #3034

[ggwpez]

Rough idea of this issue is done. More concrete follow up issues were created.