feat(icon): Add SVG icon for storygraph

What does this PR change? What problem does it solve? This PR aims to add an SVG icon for Storygraph for socials.

Was the change discussed in an issue or in the Discussions before? No

PR Checklist

[ ] This change adds/updates translations and I have used the template present here.
[X] I have enabled maintainer edits for this PR.
[X] I have verified that the code works as described/as intended.
[X] This change adds a Social Icon which has a permissive license to use it.
[X] This change does not include any CDN resources/links.
[X] This change does not include any unrelated scripts such as bash and python scripts.
[ ] This change updates the overridden internal templates from HUGO's repository.