Extend one-click-app templates to support service update overrides

[adamshand]

Is your feature request related to a problem? Please describe.

I'd like to be able to have one-click-apps mount remote storage as a Docker volume. For example, there is a Rclone plugin for Docker which allows the mounting of S3 buckets inside of containers. This allows containers which require persistent storage to be moved (or fail over) between swarm nodes.

More details at: #1956

Describe the solution you'd like

CapRover supports remote volumes via service update overrides, eg.

TaskTemplate:
  ContainerSpec:
    Mounts:
      - Type: volume
        Source: memos-rclone-b2
        Target: /var/opt/memos
        VolumeOptions: 
          DriverConfig:
            name: rclone
            Options:
              remote: b2:applications/memos
              vfs-cache-mode: full

However, there is currently no way to include a service override inside a one-click-app template.

If one-click-app templates were extended to support service overrides, this would allow easy provisioning of apps which require persistent storage in a way which also allows fail over between swarm nodes.