Add generation using configured `TileAtlas` to UI

[OliverVea]

Requirements:

• New page is created at project/{projectId}/generate
• Page has two columns: input and output
• Input column allows the user to specify:
  • Input/ouput grid size
  • Brushes to be used for generation
• Output column allows the user to:
  • View a generation from the brushes
  • Button for manually regenerating the output

Notes:

This is an MVP and will be expanded later