Add SpaNorm sticker

[bhuvad]

Adds a sticker for the SpaNorm package (in the current Bioconductor release).

This replaces #297, which also contained a sticker for a package not yet in Bioconductor. As suggested there, this PR contains the SpaNorm sticker only, and is based on current devel.

• I have read the CONTRIBUTING.md file.
• I have updated the README.md file in the main repository folder to include the new sticker.
• I have created a README.md file in the new sticker's folder.
• The README.md file in the new sticker's folder includes the following metadata:
  • Sticker / Package / Event name
  • Designer name and maintainer name (if different)
  • License information (otherwise, CC0 1.0 Universal Public Domain License applies by default)
  • Preview image of the sticker (with ~200px height)
  • Brief description of the sticker (optional)

Checklist

• The sticker is directly related to a Bioconductor package or project
• The sticker is in PNG, PDF, or SVG format (PNG and SVG provided)
• The PNG sticker height is 2 inches (5 cm) and resolution is at least 300 dpi (1181 px tall, about 600 dpi)
• The sticker is in a new folder with the same name as the sticker
• The sticker has a transparent background
• The sticker is licensed with a CC-BY-type license (otherwise, CC0 1.0 Universal Public Domain License applies by default)
• Sticker files are under 500 KB each