Revert "feat: remove unmaintened modules (#443)"

This reverts commit b1434e34d0.

attachment_s3/__manifest__.py

@@ -0,0 +1,19 @@
+# Copyright 2016-2021 Camptocamp SA
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
+
+
+{
+    "name": "Attachments on S3 storage",
+    "summary": "Store assets and attachments on a S3 compatible object storage",
+    "version": "15.0.1.0.0",
+    "author": "Camptocamp,Odoo Community Association (OCA)",
+    "license": "AGPL-3",
+    "category": "Knowledge Management",
+    "depends": ["base", "base_attachment_object_storage"],
+    "external_dependencies": {
+        "python": ["boto3"],
+    },
+    "website": "https://github.com/camptocamp/odoo-cloud-platform",
+    "data": [],
+    "installable": False,
+}