Replace println! with log functions (info!, warn!, etc)

[gbryant-arm]

Requested feature
Replace println! with log functions (info!, warn!, etc).
Use debug! for dumping debugging material, e.g. in https://github.com/veracruz-project/veracruz/blob/main/runtime-manager/src/platforms/linux.rs#L261

Motivation
println! is still used extensively, especially in the Runtime Manager. This degrades performance and is potentially dangerous

[dreemkiller]

@gbryant-arm how's the status on this? I think it's complete, but can't be sure

[gbryant-arm]

When running VOD with log level set to info, I'm getting a log over 15K lines.
I'd suggest we replace info! with debug! or trace! for most debug messages that keep showing up. Cf. tls_data() and read_tls_data() in veracruz-server/src/platforms/linux.rs

[mathias-arm]

I only see 3 places left:

• veracruz/nitro-runtime-manager/src/nitro_runtime.rs

  Line 31 in d872ec8

  println!("runtime_manager_nitro::attestation started");

• veracruz/runtime-manager/src/managers/mod.rs

  Line 276 in d872ec8

  eprintln!("Enclave debug message \"{}\"", message);

• veracruz/runtime-manager/src/managers/mod.rs

  Line 279 in d872ec8

  "Enclave returns error code {} and message \"{}\"",

The last two seem to be essentially dead code.