Add {uuid} in path template when using local storage or S3

Add an addition tag `{uuid}` to the `replacePathTemplate`.

It is a workaround to leak the public links of a resource when using S3-based object storage. Currently, all resource blobs stored in S3 (R2, OSS) are set to be public. It is insecure as the resources for the private memos are also accessible on the Internet. Using an additional {uuid} might reduce this risk.

Meanwhile, it is also possible to avoid filename conflict