chore: consolidate workspace settings [MSRV 1.64+]

[nyurik]

• Move common workspace settings to the [workspace] sections in the root.
• Add common clippy lint configuration

@rustbot label +stable-nominated

[rustbot]

r? @tgross35

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[nyurik]

@tgross35 sadly we can't use workspace settings inheritence until 1.64, which stabilized workspace-inheritance :(

[tgross35]

Ah, I was thinking it worked for some fields before then. We can land changes that don't depend on that like removing build = "build.rs", but organization improvements in this repo aren't enough to justify a user-facing new MSRV. We'll likely be bumping it sometime later this year, but until then

@rustbot blocked

[nyurik]

@tgross35 thx, I created a #4408 for that