Optimize GitHub avatar image loading by appending the s (size) query parameter to avatar URLs.

Goal: Reduce bandwidth usage by requesting appropriately sized images instead of full-resolution originals.

Changes:

1. src/component/GitHubUser.mjs:
   • Display size is 32px.
   • Append &s=64 (for 2x DPI) to avatarUrl_.
2. src/component/GitHubOrgs.mjs:
   • Display size is 20px.
   • Append &s=40 (for 2x DPI) to avatar_url.

Logic:

• Check if URL already has query parameters (it usually does, e.g., ?v=4).
• Append &s=SIZE or ?s=SIZE accordingly.