Add link to Example Live Scripts in README

[rly]

Motivation

Mathworks requested that we create a new repo to host example MATLAB Live Scripts and link to that repo from the MatNWB README to help show that this is a MatNWB community toolbox project.

This is important for getting Mathworks internal processes to hire people to work on the example Live Scripts.

Checklist

• Have you ensured the PR description clearly describes the problem and solutions?
• Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
• If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?

[codecov]

Codecov Report

Merging #454 (cd7a775) into master (2491b10) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #454   +/-   ##
=======================================
  Coverage   87.48%   87.48%           
=======================================
  Files         127      127           
  Lines        5232     5232           
=======================================
  Hits         4577     4577           
  Misses        655      655           

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more