feat: add url entries

[TrigamDev]

Summary

Allows for adding URL entries (entries representing a URL).

Closes #734

Checklist

• Allow adding URL entries, creating a .url file representing the URL.
• Allow for editing the URL of URL entries.
  • Needs careful consideration as not to edit any other parts of the .url file.
• Possibly provide a render of the webpage a URL entry represents (optional).

Tasks Completed

• Platforms Tested:
  • Windows x86
  • Windows ARM
  • macOS x86
  • macOS ARM
  • Linux x86
  • Linux ARM
• Tested For:
  • Basic functionality
  • PyInstaller executable