add cargo config to workspace

.cargo/config.toml

@@ -0,0 +1,11 @@
+# uncomment this if you have mold linker installed
+
+# [target.x86_64-unknown-linux-gnu]
+# linker = "/usr/bin/clang"
+# rustflags = ["-C", "link-arg=--ld-path=/usr/bin/mold"]
+
+[profile.release]
+strip = true
+opt-level= "s"
+lto = "thin"
+codegen-units = 1