chore: add form_type parameter argument to db (#17920)

`form_type` is a new parameter field in the terraform provider. Bring
that field into coder/coder.

Validation for `multi-select` has also been added.

coderd/database/queries/templateversionparameters.sql

@@ -5,6 +5,7 @@ INSERT INTO
         name,
         description,
         type,
+        form_type,
         mutable,
         default_value,
         icon,
@@ -37,7 +38,8 @@ VALUES
         $14,
         $15,
         $16,
-        $17
+        $17,
+        $18
     ) RETURNING *;
 
 -- name: GetTemplateVersionParameters :many