[ticket/17153] Add basic avatar config file for installer

It doesn't actually add proper avatar functionality to the installer but
provides the necessary base classes for templating.

PHPBB3-17153

phpBB/config/installer/container/services.yml

@@ -1,5 +1,6 @@
 imports:
     - { resource: services_installer.yml }
+    - { resource: services_avatar.yml }
     - { resource: ../../default/container/services_event.yml }
     - { resource: ../../default/container/services_filesystem.yml }
     - { resource: ../../default/container/services_http.yml }

phpBB/config/installer/container/services_avatar.yml

@@ -0,0 +1,25 @@
+services:
+    avatar.manager:
+        class: phpbb\avatar\manager
+        arguments:
+            - '@config'
+            - '@dispatcher'
+            - '@avatar.driver_collection'
+
+    avatar.helper:
+        class: phpbb\avatar\helper
+        arguments:
+            - '@config'
+            - '@dispatcher'
+            - '@language'
+            - '@avatar.manager'
+            - '@path_helper'
+            - '@user'
+
+    # ----- Avatar drivers -----
+    avatar.driver_collection:
+        class: phpbb\di\service_collection
+        arguments:
+            - '@service_container'
+        tags:
+            - { name: service_collection, tag: avatar.driver }