add a processor to filter out linked entities by path component

Problem/Motivation

A problem we have with various link processors -- entity reference, link fields, body text links -- is that they will pull nodes from far off places in the site, and that causes a pull operation to time out (see also 🐛 pulled dependencies don't participate in the batch, risk of PHP execution timeouts Active ).

If we're pulling a node with path /section/foo, then our intent is for related child nodes to be pulled too, but a node with path /whatever/something-else should be skipped.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes