Add useful default custom receive functions

[jonathan-ostrander]

Instead of defining the default CustomReceiveFunctions as an empty partial function, this uses the existing partial function defined in ValueDecoder as a default.

The issue is demonstrated by the following code:

val client =
  Postgres.Client()
    .withCredentials("postgres", None)
    .database("postgres")
    .newRichClient(s"localhost:5432")

Await.result(client.execute("CREATE TABLE person (name VARCHAR(255), age Int)"))
Await.result(client.execute("INSERT INTO person (name, age) VALUES ("Bob", 45), ("Alice", 25)"))

println(Await.result(client.select("SELECT name, age FROM person") { row =>
  val name = row.getAnyOption("name") match {
    case Some(n: String) => n
    case _ => sys.error("failed to read name")
  }
  val age = row.getAnyOption("age") match {
    case Some(a: Int) => a
    case _ => sys.error("failed to read age")
  }
  (name, age)
}))

// expected behavior: Vector(("Bob", 45), ("Alice", 25))
// current behavior: java.lang.RuntimeException: failed to read name

Obviously, to avoid this I could just use row.get which uses the existing ValueDecoders for Int and String but when trying to define more complex behavior for decoding like the library quill tries to generalize here with partial functions it's pretty easy to run into this issue and it's pretty difficult to debug without knowledge of how decoding works in both libraries.