Update Actix Web to version 4:

• Update the actix-web crate to version 4.0.1.
• Update the awc crate to version 3.0.0.
• Update the actix-http crate to version 3.0.4.
• Update the actix-tls crate to version 3.0.3.
• Update the actix-server crate to version 2.1.1.
• Update the actix-web-codegen crate to version 4.0.0.
• Update the actix-router crate to version 0.5.0.
• Update the actix-service crate to version 2.0.2.
• Update the actix-utils crate to version 3.0.0.
• Update the actix-codec crate to version 0.5.0.

This update also includes related updates for some actix dependencies:

• Update the time crate to version 0.3.9.
• Update the time-macros crate to version 0.2.4.
• Adapt the package for the serde_qs crate to the actix-web update.
• Initial packaging of the firestorm and num_threads crates.