Enable Surge build on master with drafts

To make it easier to work on draft pages across multiple merge requests, for example with !109 (merged) creating a skeleton and future MRs filling those pages in before they get published, we need to have some sort of preprod for the documentation. Enabling the existing Surge build to use the master branch might be the easiest way. This build needs to include draft pages, but the production builds should still not include any drafts.