Introduce cdk-sql-common

The primary purpose of this new crate is to have a common and shared codebase
for all SQL storage systems. It would force us to write standard SQL using best
practices for all databases.

This crate has been extracted from #878

crates/cdk-sql-common/src/mint/auth/migrations.rs

@@ -0,0 +1,5 @@
+/// @generated
+/// Auto-generated by build.rs
+pub static MIGRATIONS: &[(&str, &str)] = &[
+    ("sqlite/20250109143347_init.sql", include_str!(r#"./migrations/sqlite/20250109143347_init.sql"#)),
+];