fixup

- trim dependency tree
- use `postgres-native-tls`
- add ssl option with no extra certificate
- dry up some code

Author: tankyleo

rust/Cargo.lock

@@ -11,8 +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 }
-openssl = "0.10.75"
-postgres-openssl = "0.5.2"
+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"] }