Add the option to make TLS connections to the database

Also add the option to specify an additional root certificate for
the client to trust.

Author: tankyleo

rust/Cargo.lock

@@ -11,6 +11,8 @@ tokio-postgres = { version = "0.7.12", features = ["with-chrono-0_4"] }
 bb8-postgres = "0.7"
 bytes = "1.4.0"
 tokio = { version = "1.38.0", default-features = false }
+native-tls = { version = "0.2.14", default-features = false }
+postgres-native-tls = { version = "0.5.2", default-features = false, features = ["runtime"] }
 
 [dev-dependencies]
 tokio = { version = "1.38.0", default-features = false, features = ["rt-multi-thread", "macros"] }