feat(nargo): Add nargo test command to run all unit tests

[jfecher]

Related issue(s)

Resolves #610

Description

Adds the nargo test command to collect all functions with the new #[test] attribute and prove each of them, notifying the user if any test fails.

Summary of changes

• Adds nargo test command
• Adds #[test] attribute
• Run the frontend on the entire crate beforehand to minimize repeated work
• Collect all #[test] functions afterward and run the backend on each.
• nargo test accepts an optional pattern argument to only run tests with names containing the given pattern.

Dependency additions / changes

• aztec_backend should be updated from this PR: Remove timing printlns acvm-backend-barretenberg#49 to clean up testing output. Otherwise the timing information is printed in between each running test.

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Additional context

Tasks yet to be done: (all completed):

• Clean up test output more on success (requires Remove timing printlns acvm-backend-barretenberg#49)
• Colored output to make it easier to read at a glance
• Verify functions with #[test] attribute have no parameters
• Use catch_unwind to stop any panics that may happen when running a test - we cannot do this actually since our Driver type makes use of internal mutability.

Example output running 2 tests (1 passing, 1 failing) (after aztec_backend update now):

Running 2 test functions...
Testing my_passing_test... ok
Testing my_failing_test... error: 
   ┌─ /.../example/src/main.nr:14:15
   │
14 │     constrain false;
   │               ----- Constraint is always false

error: aborting due to 1 previous errors
my_failing_test failed

1 test failed
exit 1

[jfecher]

Cannot add catch_unwind since a Driver needs to be put in the lambda and it contains data which is not unwind safe (contains interior mutability).

[jfecher]

This PR is ready for review again