it's not clear what is public zenoh API just by looking at sources

[milyin]

Describe the release item

All zenoh modules in lib.rs are exported as public (pub mod session, etc)
Module prelude and root lib.rs reexports some of entities, but not all of them. This makes not clear for user what to import. Rust-analyzer shows multiple pieces of advice for same name.

I think to make things in order it makes sense to do these steps:

1. in "lib.rs" remove all pub from mod declarations
2. explicitly reexport public API from single place (prelude and lib.rs)

This will make API observable when looking at sources

[milyin]

The task #806 is actually subtask of this

[milyin]

Done in dev/1.0.0 branch by reexporting all API through lib.rs