feat(send): add role for self-hosted Send file-share service

Deploys timvisee/send with a Redis backend behind Traefik. Supports
local-disk or S3 storage (e.g. via the garage role). Uses the shared
`*_domains` list convention so the router can accept internal *.int.*
names alongside the canonical BASE_URL host.

roles/send/vars/main.yml

@@ -0,0 +1,3 @@
+#SPDX-License-Identifier: MIT-0
+---
+# vars file for send