Make the chatbot obey the object name blacklist

Summary: Fixes T11508. The config entry remarkup.ignored-object-names already contains a blacklist of object names that should be ignored in the web UI. This change makes that blacklist also apply to the chatbot. This makes it possible to have a chatbot ignore things like V1, V2, Q1 and any other phrases the user may not want to generate links to objects.

Test Plan: Create objects (tasks, slowvotes, etc.) then mention the object names in chat (with the bot running). The bot should respond with helpful links to the given objects. Then add the object names to the blacklist through the config web UI. This apparently triggers the bot to restart itself. Then mention the object names in chat again. The bot should no longer respond with links because those object names have been added to the blacklist regex.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley

Maniphest Tasks: T11508

Differential Revision: https://secure.phabricator.com/D16442