Migrate install rewriting to new rewriters

pg4wp/rewriters/DropTableSQLRewriter.php

@@ -0,0 +1,17 @@
+<?php
+
+class DropTableSQLRewriter extends AbstractSQLRewriter
+{
+    public function rewrite(): string
+    {
+        $sql = $this->original();
+
+        $pattern = '/DROP TABLE.+ [`]?(\w+)[`]?$/';
+        preg_match($pattern, $sql, $matches);
+        $table = $matches[1];
+        $seq = $table . '_seq';
+        $sql .= ";\nDROP SEQUENCE IF EXISTS $seq;";
+
+        return $sql;
+    }
+}