Nerdctl as a library (documentation and API work)

[apostasie]

What is the problem you're trying to solve

See #4337 for context.

Building a simple cli that just runs a container is not trivial for newcomers, and certainly requires significant familiarity with nerdctl internals to get it to work.

Furthermore, the "API" is largely undocumented, and there are a number of extra things to implement on-top of using pkg (hooking of logging and oci-hooks).

Describe the solution you'd like

Suggesting:

1. documentation
2. express a better / simpler API hiding away some of the complexity

Additional context

No response