Add Gander Performance Tests

Problem/Motivation

This module does heavy lifting on texts, so would it perhaps make sense to monitor the performance?

For a useful test, that would mean we'd have to generate a lot of content and measure the vanilla Drupal installation against the same with Glossify enabled.

https://www.drupal.org/docs/develop/automated-testing/performance-tests →

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes