Test for Drupal 10.x on Mysql 8 and 11 on MySQL 5.7

[dafeder]

Some hosting solutions are already on MySQL 8 for Drupal 10. At the same time, other hosting solutions (including Acquia) still do not support MySQL 8 even for Drupal 11, and require use of the backport db driver. We should add:

• At least one combination of Drupal 10.x and MySQL 8 to the CircleCI testing matrix
• Drupal 11 + MySQL 5.7 in the matrix, and add the backport module as a dependency.

[dafeder]

Blocked by #4356