feat(mito): Combine the original and procedure's implementation (#1468)

* fix(mito): Add metrics to mito DDL procedure

* feat(mito): Use procedure's implementation to create table

* feat(mito): Use procedure's implementation to alter table

* feat(mito): Use procedure's implementation to drop table

* style(mito): Fix clippy

* test(mito): Fix tests

* feat(mito): Add TableCreator

* feat(mito): update alter table procedure

* fix(mito): alter procedure create alter op first

* feat(mito): Combine alter table code

* fix(mito): Fix deadlock

* feat(mito): Simplify drop table procedure

src/file-table-engine/src/engine/immutable.rs

@@ -234,6 +234,9 @@ impl EngineInner {
             return if request.create_if_not_exists {
                 Ok(table)
             } else {
+                // If the procedure retry this method. It is possible to return error
+                // when the table is already created.
+                // TODO(yingwen): Refactor this like the mito engine.
                 TableExistsSnafu { table_name }.fail()
             };
         }