Better support for monorepos

Currently, when having multiple deno projects in the same repository and all deployed in Deno Deploy they all get a deployment trigger when I commit to one of the folders. Is it possible to declare specifically what folder/projects should be deployed from a repository? Here's an example of a mono-repo I have https://github.com/aabedraba/dotcom

On the other hand, it affects the way relative paths work between local development vs deployment, because in local development your `Deno.cwd()` would be `PATH_IN_FILESYSTEM/project-1` while in Deno Deploy it would be `/src`. For this case, I had to include a conditional to make this work in local development and production https://github.com/aabedraba/dotcom/blob/master/www/routes/index.tsx#L72-L78