feat(ui-babel-preset): allow for specifying additional import transforms

TEST PLAN:
- Automated tests should pass
- yarn start and yarn dev should still run docs

Change-Id: Iaf2f9dea9a805ef1697a7aa5e7559ce653af585c
Reviewed-on: https://gerrit.instructure.com/c/instructure-ui/+/223814
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Ken Meleta <kmeleta@instructure.com>
Product-Review: Steve Jensen <sejensen@instructure.com>
QA-Review: Daniel Sasaki <dsasaki@instructure.com>
Visual-Regression-Test: Steve Jensen <sejensen@instructure.com>

Author: serikjensen

packages/ui-babel-preset/lib/index.js

@@ -30,7 +30,8 @@ module.exports = function (context, opts = {
   coverage: false,
   node: false,
   removeConsole: false,
-  transformImports: true
+  transformImports: true,
+  importTransforms: {}
 }) {
   const envPresetConfig = opts.node ? getNodeEnvConfig() : getWebEnvConfig(opts)
 
@@ -62,7 +63,8 @@ module.exports = function (context, opts = {
             if (!matches || !matches[1]) return
             return matches[1].replace(new RegExp('/es/'), '/lib/')
           }
-        }
+        },
+        ...(opts.importTransforms || {})
       }
     ])
   }