Documentation changes wishlist

[pietroalbini]

This issue contains a list of the changes I want to make to the documentation:

• Add an installation guide for Windows (isssue Add documentation about installing botogram on Windows #18)
• Add dependencies installation instructions on the installation chapter
• Rename the tutorial to quickstart
• Add a proper tutorial
• Add a narrative chapter about creating your bot
• Add a narrative chapter about a bot's structure
• Add a narrative chapter about sending messages
• Add a narrative chapter about commands
• Add a narrative chapter about localization (issue Language overhaul #46)
• Add code example to API reference

This list may grow.