Gemini/Spartan client in Electron.

• Can make gemini requests
  • Handle 1x status codes
  • Handle client certificates
• Can make spartan requests
  • Handle spartan input links
    • Text input
    • File input (currently not working)
• Render gemtext
  • Basic line types
    • Preformatted alt text
  • Advanced line types
  • Correctly render spartan input links
• Top menu
• Bookmarks
• Config screen
• Custom CSS theming (for UI and pages)
  • Per-capsule theming?