1. Add "grabbing" cursor while dragging items:

2. Make project board only drag via their header, not via their whole
body.

3. Fix some cursor problems in projects
4. Move shared options into `createSortable`.
(cherry picked from commit 7fda109aba6cd077343edef086b2f2ff60124f78)
Previously, `sortablejs` was imported twice, once synchronously and once
asynchronously, leading to webpack creating duplicate output code (once
in the index bundle, and once in a separate chunk). Fix this by always
asynchronously importing it. This was one of the build warnings observed
when trying to build with vite.