Support for monorepo build is missing in @web/dev-server-storybook

[hardikpthv]

Currently when @web/dev-server-storybook is used in the Monorepo particularly with yarn workspaces in which the dependencies are managed centrally instead of package-level, the building of the storybook feature breaks on the following issue:

node_modules/@web/dev-server-storybook/node_modules/babel-plugin-bundled-import-meta/index.js:68
                                        throw new Error('Does not match any mappings or bundleDir.');

From quick investigation, the change in rollup base config, by adding support for packageDir, would fix the issue.