docs: add kjschmidt913 as a contributor for infra, test, and 2 more

[allcontributors]

Adds @kjschmidt913 as a contributor for infra, test, code, data.

This was requested by blaiszik in this comment

[skip ci]

[what-the-diff]

PR Summary

• New Contributor Added
  A new contributor known as "KJ Schmidt" is added to the .all-contributorsrc file. This file contains information about each contributor – their name, profile link, and what contributions they've made.
• Updated Contributors Badge
  The "All Contributors" badge in the README.md file has been updated to reflect the current number of contributors. It now displays '2' instead of '1', indicating the addition of the new contributor.
• Updated Contributors Table
  The contributors table in the README.md file has been updated with new row for "KJ Schmidt". This table shows a visual representation of all contributors, including their avatar, a link to their profile, and an overview of their contributions.