Integrate Clippy into the project

[blyxyas]

This PR integrates Clippy into the project.
A user can run the clippy profile with a local Clippy build, with the --clippy flag targetting to the Clippy executable:

$ cargo run --bin collector  -- bench_local +nightly --profiles Clippy --clippy ../clippy/target/release/cargo-clippy

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But I'm having some problems with the bot integration, so some feedback and tips in those files would be very appreciated.

• Would the bot run this on every commit, where is it configured? (we don't want to run it every commit)
  Thanks for the feedback ❤️

[Kobzol]

Hi, thanks for the PR! I left some comments. I wonder what was your motivation for this PR? Do you work on Clippy and want to measure its performance on crates?

[blyxyas]

I wonder what was your motivation for this PR? Do you work on Clippy and want to measure its performance on crates?

Yep, we wanted a tool for measuring Clippy's performance on crates. Not for every commit, but to run once every 7 days or when triggered by a maintainer (We don't need a lot of active monitoring + Clippy benchmarking is really resource-intensive)

[blyxyas]

This new commit should be just like the first one, but discarding anything server-related =^w^=

[Kobzol]

Thanks for the changes. Some problems that cause CI to fail still have to be resolved, as per the other comments.

Also, as per #1724 (comment), we shouldn't include Clippy in Profile::all() for now. Let's just remove it from there, that should fix collection on the server. Later we might add it back once we're sure that clippy benchmarks can be run on the perf server.

[Kobzol]

Great, thanks for the changes! :)