Implement PgHasArrayType with derive(sqlx::Type)

[laralove143]

Is your feature request related to a problem? Please describe.
Currently if one wants to use a type in an array they have to implement the trait manually:

impl PgHasArrayType for Foo {
    fn array_type_info() -> PgTypeInfo {
        PgTypeInfo::with_name("_foo")
    }
}

This is unpredictable and can get repetitive with many types

Describe the solution you'd like
Deriving sqlx::Type implicitly implements this trait following the _{name} format

Describe alternatives you've considered

• There could be another derive for this: derive(sqlx::Type, sqlx::TypeArray)
• There could be an attribute to do this #[derive(sqlx::Type)] then #[sqlx(array)]
• It could be derived implicitly by default, but that could be disabled or renamed with #[sqlx(array_name = "__foo")] or #[sqlx(array = false)]

[abonander]

Closed by #3252