feat(enclave): optional backup

[hu55a1n1]

This PR does the following ->

• Change the Host API to make the backup/restore optional.
• Adds a --no-backup option to the quartz CLI (and example enclaves) that defaults to false.
• Improve log coloring (log levels are now colored, but ANSI colors in log messages are still not fixed - this is due to an upstream issue, see Regression: New tracing-subscriber breaks ANSI color and styling support tokio-rs/tracing#3369 and other related issues on the tracing repo) - tried reverting to old versions of tracing but that creates other problems, so not fixing in this PR.
• Default to info level logs - this prints things related to backups, enclave status etc. that were previously not printed.
• Fixed --pccs-url so it can be set from the quartz CLI which wasn't the case previously.

[MSalopek]

LGTM!