Bumped @tryghost/nql to 0.13.0 and removed local mongo-knex link

ref TryGhost/NQL#152

- the aggregate relation support is now published as nql 0.13.0 / mongo-knex 0.10.0, so the temporary pnpm `link:` override pointing at a local NQL checkout is no longer needed
- bookshelf-filter pins nql@0.12.10 exactly, so nql is force-resolved to the catalog version via a pnpm override to make sure filter queries are built with aggregate relation support
- removed the nql@0.12.10 packageExtension as nothing resolves that version anymore and 0.13.0 declares its lodash dependency properly

Author: kevinansfield