Packages do not specify an `exports` field

Packages in the workspaces should set the exports field in the package.json file. As Node.JS doesn't read the module field, the ESM output may be skipped if the exports field is not added.

Specifying the exports field also prevents modules that are written in ESM from being interpreted as CommmonJS. For example, it is currently possible to make the following import:

import foo from "@patternfly/react-drag-drop/dist/esm/next/components/DragDrop/DragButton"

Since there is no type specified this file would be considered CommonJS, even though the source is actually written in ESM.

The exports field supplants the main and module fields, which should be removed when the exports field is introduced. This would be considered a breaking change.

This is part of a series of issues resulting from publication linting introduced under #10764

Review the workspace package.json files and the publication linting context from #10764. Add exports entries for the packages, remove the superseded main and module fields where applicable, and verify that the documented ESM import is resolved correctly by Node.js.