Cargo caching with forklift

[AndWeHaveAPlan]

This PR adds cargo caching feature with custom 'forklift' tool
Forklift acts as RUSTC_WRAPPER, intercepts rustc calls and stores produced artifacts in S3 bucket (see forklift readme for detailed description)

All settings are made in .forklift job's before_script and affect all jobs that extend .docker-env job

To disable feature set FORKLIFT_BYPASS variable to true in project settings in gitlab

[rcny]

Well done! 🙏

[bkchr]

Any numbers on the speed up for the test-linux-stable job?

[AndWeHaveAPlan]

Any numbers on the speed up for the test-linux-stable job?

Unfortunately, not good enough. Build speedup is 5-25% (depending on the job). This is because the current version only caches crates from crates.io. There are still some issues with the substrate-wasm-builder cache

[bkchr]

There are still some issues with the substrate-wasm-builder cache

And what is with path dependencies? That also doesn't work?

[AndWeHaveAPlan]

And what is with path dependencies? That also doesn't work?

For simplier repos (such as cargo) everything seems to be ok. But for polkadot-sdk I get errors E0460 (found newer version of crate) and E0463 (can't find crate). I'm still investigating if it is only substrate-wasm-builder crates problem. Right now I'm working on the idea that forklift may mess up cached artifacts with "real" target dir and builder "subtargets" under some conditions