Screen layout and primary navigation

[jhorback]

Description

Implement the main layout for Plotmap which includes the primary navigation panel and the content panel.

Acceptance Criteria

• A split pane view exists with the navigation panel on the left and the main content on the right.
• The navigation panel has links for: Plotmap, Themes, Characters, and Settings.
• When navigating through each top level, the appropriate secondary level of navigation appears.
• When navigating through each top level, the appropriate content appears in the main content area.
• The URL updates appropriately so that a page refresh keeps the user on the same page.

Note: The data to drive this can be mock data.

Development Tasks

• Add tests
• Has design file
• Supports dark-theme
• Update documentation

Implementation Details

Navigation Panel

The navigation panel will contain top level links for:

• Storyboard
• Characters
• Settings

The secondary level of navigation can just show that it has switched (i.e. Plotmap will contain the text "Plotmap").

URLs

This is an initial guess on what the URLs should be.

• Stories: / (root url is stories)
• Plotmap: /story//plotmap
• Themes: /story//theme/
• Characters: /story//characters/
• Settings: /story//settings/