We recently added documentation disambiguating the terminology of the
allocation/task working directories. This changeset adds an internals document
that describes in more detail exactly what does into the allocation working
directory, how this interacts with the filesystem isolation provided by task
drivers, and how this interacts with features like `artifact` and `template`.
Co-authored-by: Charlie Voiselle <464492+angrycub@users.noreply.github.com>