s3: add multi tenant support for Cubbit

backend/s3/provider/Cubbit.yaml

@@ -4,6 +4,7 @@ region:
   eu-west-1: Europe West
 endpoint:
   s3.cubbit.eu: Cubbit DS3 Object Storage endpoint
+  s3.{tenant_name}.cubbit.eu: Multi-tenant endpoint - replace {tenant_name} with your actual tenant name. Do not select this directly
 acl: {}
 bucket_acl: true
 quirks:

docs/content/s3.md

@@ -5132,7 +5132,9 @@ can follow this [guide](https://docs.cubbit.io/getting-started/quickstart#api-ke
 to retrieve these keys. They will be needed when prompted by `rclone config`.
 
 Default region will correspond to `eu-west-1` and the endpoint has to be specified
-as `s3.cubbit.eu`.
+as `s3.cubbit.eu`. If you set a custom tenant endpoint, you must use
+`s3.{tenant_name}.cubbit.eu`, because the generic `s3.cubbit.eu` endpoint will not
+work in this case.
 
 Going through the whole process of creating a new remote by running `rclone config`,
 each prompt should be answered as shown below:
@@ -5145,7 +5147,7 @@ env_auth> false
 access_key_id> YOUR_ACCESS_KEY
 secret_access_key> YOUR_SECRET_KEY
 region> eu-west-1 (or leave empty)
-endpoint> s3.cubbit.eu
+endpoint> s3.cubbit.eu (or s3.{tenant_name}.cubbit.eu)
 acl>
 ```