Allow path to be altered before being processed

Problem/Motivation

Actually title resolvers can resolve titles by processing single path elements.
In some cases, like when working with Schema.org paths or API paths, it could be useful to alter the source path before being processed in order to avoid resolving path elements which are meaningless for the end users.

Steps to reproduce

Proposed resolution

Add a new breadcrumb_manager_path_alter hook to let other modules altering the breadcrumb path before getting processed.

Remaining tasks

User interface changes

API changes

Data model changes