Improve CLI hints

[mcalancea]

Makes a couple of changes to improve the experience of passing hints to guest programs via the CLI.

• Eliminates debug_memory_ranges from src/e2e.rs because it fails when hints are non-empty.
• Introduces a --structured-hints option for bin/e2e.rs. This parses a sequence of u32s in decimal notation from a file and serializes them so that they can be consumed by the guest; i.e, a file containing the values N a1 a2 .. aN will produce hints such that let input: &ArchivedVec<u32> = ceno_rt::read(); in the guest will result in input = [a1, a2.. aN]. This is easier to use than the existing --hints option (now renamed to --raw--hints) which requires the user to serialize the input correctly on their own;

I think in the long-term more general solutions are required to increase compatibility of guest programs with bin/e2e.rs, but this PR is an ok compromise for my day-to-day.