Add bash lesson

[James-S-Santangelo]

• Added bash lesson
• Lesson is an amalgamation of John Ladan's lesson from UofT Coders and a third year Bioinformatics primer written by Rob Ness and Ahmed Hasan.

[James-S-Santangelo]

• Incorporated feedback.
• Also added brief section on file/directory naming (i.e. avoiding spaces)