Add some missing metadata from the Cargo.toml in preparation for publishing the package

Author: NlightNFotis

src/libcprover-rust/Cargo.toml

@@ -2,6 +2,11 @@
 name = "cprover-api-rust"
 version = "0.1.0"
 edition = "2021"
+description = "Rust API for CBMC and assorted CProver tools"
+repository = "https://github.com/diffblue/cbmc"
+documentation = "https://diffblue.github.io/cbmc/"
+license = "BSD-4-Clause"
+exclude = ["other/", "module_dependencies.txt"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html