Move all deps to workspace toml

[jsdw]

Move all of our dependencies (and version) to the workspace toml, and reference them in crates where used.

Why?

• Prevents dupe versions of crates from being used across the workspace (or, makes it very much "opt-in" and explicit if you do need this)
• Makes bumping Subxt versions easy for releasing; just one file to change
• Makes bumping Substrate dep versions easier; all in one place.
• Makes it clear how many crates we import in total; might motivate us to cut down a bit ;)

Note: package = "parity-scale-codec" is needed in each crate, because the macro uses https://github.com/bkchr/proc-macro-crate, which relies on finding that key in the local TOML (see bkchr/proc-macro-crate#34). The alternative is giving a manual crate path in all uses of the macro, but doesn't seem worth it.

[niklasad1]

Great, just remove some unintended committed files and it should be ready to go

[jsdw]

Comment moved and added files gone :)

[niklasad1]

do we want this?

[jsdw]

I debated that; I assume it's used to determine the deps to download for tests so maybe good to keep it to ensure complete consistency between us :)