Support to merge sealer images

[kakaZhou719]

Issue Description

Type: feature request
example:

i have two image :
image A is amd64 architecture.
image B is arm64 architecture.

i want to merge those two image as a new one image C.

• pack different arch image together feature: support to add multi-arch image to manifest #2180
• merge same arch image as a new one

Describe what feature you want

Additional context

Add any other context or screenshots about the feature request here.

[kakaZhou719]

for pack different arch image together

At present ,We can do it manually。

# create a manifest with the new name
sealer alpha manifest create all-in-one:v1

# add ImageID to manifest 
sealer alpha manifest add all-in-one:v1 b4aef6cb03b3(arm)
sealer alpha manifest add all-in-one:v1 a661b497f201(amd)

# inspect the result.
sealer alpha manifest inspect all-in-one:v1

Or we develop a new method:

sealer alpha manifest add amd:v1 arm:v1 -t all-in-one:v1

-t flag : specify the wanted new image name, if null, will create a new one. if not null, it must be an existed manifest name.

args: if it is a single image just add it ,if it is a manifest will add it’s s all instance no matter what platform it is.

[kakaZhou719]

for merge same arch image as a new one
this will only merge the same platform images, including layers, image specs and so on.

sealer alpha merge k8s:v1.22.15 mysql:v1 redis:v1 -t all-in-one:v1

[chatiti]

@kakaZhou719 Hi, I'm new to the program. I would like to try to solve the merge same arch image as a new one; but my question is, sealer alpha merge and sealer alpha manifest add both seem to merge two images, so why differentiate between different architectures and have two new commands? And now I think their merge implementations are similar, is this correct? Thank you for your help.