change tokio::sync::Mutex to tokio::sync::RwLock and use read()/write…

[harrison-tin]

…() instead of lock()

Signed-off-by: Harrison Tin [email protected]

What this PR does / why we need it:
This PR changes the use of tokio::sync::Mutex to tokio::sync::RwLock (used by configMap and instanceMap). RwLock uses read()/write() depending on the action of the thread instead of lock() from Mutex.
It closes #376
Special notes for your reviewer:

If applicable:

• this PR has an associated PR with documentation in akri-docs
• this PR contains unit tests
• added code adheres to standard Rust formatting (cargo fmt)
• code builds properly (cargo build)
• code is free of common mistakes (cargo clippy)
• all Akri tests succeed (cargo test)
• inline documentation builds (cargo doc)
• all commits pass the DCO bot check by being signed off -- see the failing DCO check for instructions on how to retroactively sign commits

[kate-goldenring]

LGTM! Thanks for this!

[kate-goldenring]

/version patch