Add discussion of SFTP about shell-genomics

[p-j-smith]

A discussion of sftp and perhaps Globus or rsync would be nice. However, as the workshop is already too long we would like to avoid adding too much new content.

One option would be to add an extra optional lesson, like we currently have for file manipulation. If you put the lesson in the intstructors folder, then it will be available under the intstructor's view on the site (see the file manipulation lesson for an example).