Revert "Update to Drupal 9"

Revert back so that we can continue to use the Config Installer module.

This reverts commit e5b86c7f39.

.php-version

@@ -1 +0,0 @@
-7.3.6

composer.json

@@ -17,12 +17,13 @@
     "require": {
         "composer/installers": "^1.2",
         "drupal/admin_toolbar": "^2.0",
-        "drupal/core-composer-scaffold": "^9.0",
-        "drupal/core-recommended": "^9.0",
-        "drush/drush": "^10"
+        "drupal/config_installer": "^1.8",
+        "drupal/core-composer-scaffold": "^8.8",
+        "drupal/core-recommended": "^8.8",
+        "drush/drush": "^9"
     },
     "require-dev": {
-        "drupal/core-dev": "^9.0"
+        "drupal/core-dev": "^8.8"
     },
     "conflict": {
         "drupal/drupal": "*"

tools/ansible/deploy/after-symlink-shared.yml

@@ -1,7 +1,7 @@
 ---
 - name: Install Drupal
   command: |
-    {{ release_drush_path }} site-install -y \
+    {{ release_drush_path }} site-install config_installer -y
     --account-pass=admin123
   args:
     chdir: '{{ release_drupal_path }}'

web/modules/custom/simple_message/simple_message.info.yml

@@ -1,5 +1,5 @@
 name: Simple Message
 description: Displays a simple message.
-core_version_requirement: ^8 || ^9
+core: 8.x
 type: module
-package: Custom
+package: Custom