[PR #514/e2aa655 backport][stable-1] Fix issues and documentation with integration tests after merge of #490 (#520)

* Fix issues and documentation with integration tests after merge of #490. (#514)

* Fix explanation about containers images
* Add definitive URI to the containers images
* Document that new images must be set as public
* Document makefile options possible values
* Document that any mysql and mariadb tag can be used
* Add computation of docker_image path
* Refactor pre-command to separate commands for cleaner GHA output
* Refactor to use GHA test matrix
* Cut docker_image from documentation since it's now automatic
* Document how to use run_all_test.py to display the test matrix

(cherry picked from commit e2aa655762)

* Add changelog fragment
* Cut tests for MariaDB 10.5 and 10.6 that never worked with stable-1

.github/workflows/docker-image-mysql-py310-mysqlclient211.yml

@@ -0,0 +1,19 @@
+---
+name: Docker Image CI mysql-py310-mysqlclient211
+
+on:
+  push:
+    paths:
+      - 'test-containers/mysql-py310-mysqlclient211/**'
+      - '.github/workflows/docker-image-mysql-py310-mysqlclient211.yml'
+      - '.github/workflows/build-docker-image.yml'
+
+jobs:
+
+  call-workflow-passing-data:
+    uses: ./.github/workflows/build-docker-image.yml
+    secrets: inherit
+    with:
+      registry: ghcr.io
+      image_name: test-container-mysql-py310-mysqlclient211
+      context: test-containers/mysql-py310-mysqlclient211