System level documentation

Description

Describes broadly the structure of dragoonfly as well as the utilities we made (such as the CLI).

Detailed list of changes

Explains:

• Global structure
• What happens inside a node when a command is issued
• Quickly explains interaction with other nodes
• The API / http interface
• The CLI

Related issues

This MR will:

• close #8 (closed)
• close #9 (closed)
• close #12 (closed)