reversible migrations for cli

- adds a -r flag whihc will create a reversible migration
- add revert subcommand, which reverts the last migration
- add --dry-run flag to migration run command, which list the migrations that will be applied
- updates add migration to check if all migration are of same type, i.e cannot mix and match reversible and simple migrations

sqlx-cli/src/database.rs

@@ -40,5 +40,5 @@ pub async fn reset(migration_source: &str, uri: &str, confirm: bool) -> anyhow::
 
 pub async fn setup(migration_source: &str, uri: &str) -> anyhow::Result<()> {
     create(uri).await?;
-    migrate::run(migration_source, uri).await
+    migrate::run(migration_source, uri, false).await
 }