container-image

What would you like to be added:

Please add some basic instructions for compiling the binaries to the install readme as an alternative to curl to bash.

Why is this needed:

Some folks are uncomfortable with the security implications of curl to bash

There are additional use cases where users may wish to modify the functionality of the project to better fit their needs

**Addit

In a use case of inserting primarily binary or already compressed objects, having a flag to just disable compression seems feasible.
This would leave the mediaType as just application/vnd.oci.image.layer.v1.tar

https://github.com/dragonflyoss/image-service/blob/48a125074fdc3f8d600f0d18d1ef0b7ab89c704d/src/bin/nydusd/fusedev.rs#L327

If a non-canonical path, e.g. ./mydebug/mntpoint is passed, the above function failed to find the mount point as expected.

Looks like we need to ensure is_mounted() get a canonical path, either by itself or the caller.