Add forklift to remaining jobs (#3236)

Add [forklift
caching](https://gitlab.parity.io/parity/infrastructure/ci_cd/forklift/forklift)
to remainig jobs

by .sh and .py scripts:
- cargo-check-each-crate x6 (`.gitlab/check-each-crate.py`)
- build-linux-stable (`polkadot/scripts/build-only-wasm.sh`)

by before_script:
- build-linux-substrate
- build-subkey-linux (with `.build-subkey` job)
- cargo-check-benches x2

**To disable feature set FORKLIFT_BYPASS variable to true in [project
settings in
gitlab](https://gitlab.parity.io/parity/mirrors/polkadot-sdk/-/settings/ci_cd)**
(forklift now handles FORKLIFT_BYPASS by itself)

.gitlab/check-each-crate.py

@@ -55,7 +55,7 @@ for i in range(0, crates_per_group + overflow_crates):
 
 	print(f"Checking {crates[crate][0]}", file=sys.stderr)
 
-	res = subprocess.run(["cargo", "check", "--locked"], cwd = crates[crate][1])
+	res = subprocess.run(["forklift", "cargo", "check", "--locked"], cwd = crates[crate][1])
 
 	if res.returncode != 0:
 		sys.exit(1)