chore: remove individual test workspaces

[xJonathanLEI]

Same as #1566 but for the tests folder. Makes these changes:

• adds a root workspace at tests/Cargo.toml and removes all individual test workspaces;
• fixes all compilation errors in tests resulting from being unmaintained;
• adds a CI job for linting and building crates in tests.

Using a single worksapce dramatically reduces compilation time. On a Macbook Pro with M3 Max, running make in the tests folder on a fresh repo clone took 5m28.870s, but this PR brings it down to 0m43.894s, down by 86%.

[github-actions]

SP1 Performance Test Results

Branch: jon/tests_workspace
Commit: b32646d
Author: xJonathanLEI

program	cycles	execute (mHz)	core (kHZ)	compress (KHz)	time	success
fibonacci	11291	0.18	5.92	0.16	1m12s	✅
ssz-withdrawals	2757356	17.34	63.43	17.31	2m39s	✅
tendermint	12593597	6.60	165.03	63.53	3m20s	✅