Create a LaTeX template for theoretical documentation

[stenbergd]

Create a LaTeX template for the theoretical report/doc and add the .tex file to the repository.

A template exists currently in the dragonfly-fcb repo

[adam-at-epsilon]

There is one template named doc/dragonfly-report-template.tex in this repo, it's a copy of the one in dragonfly-fcb.

Or is there another template?