Feature request: calculate Swarm reference hash of content

[crtahlin]

Would like to have a feature available, to calculate Swarm reference hash of content.

Use case: to be able to verify that the hash of downloaded content is as expected.

[Cafe137]

The new swarm-cli release has a hash function that calculates the Swarm hash of a single file. Do note that this corresponds to the /bytes endpoint, not the /bzz.

This feature will be improved upon for full support.

[0xCardiE]

This would be needed on directories mostly.
For example, if you upload a webpage it is a directory, if you upload NFTs it is a directory etc

Doing just for files isn't really solving the issues we created.
Can we have it for directories, please?