[lib] Move WebNavInfo to lib

Summary:
We're moving this to lib so we can move InitialReduxStateResponse.

Depends on D10891

Test Plan: flow and CI and close reading of changes. Used IDE Refactor -> Move tool to make this change.

Reviewers: ashoat, ginsu, tomek

Reviewed By: ginsu

Differential Revision: https://phab.comm.dev/D10892