Clean up each format’s template by moving format specific logic into
module, with overrides in format presenters.
* Content item title
* Context based on document type
* Long title length
This makes it difficult to include titles with the wrong attributes, eg
missing long title length. It also highlights which formats are
Previously, by setting `m[:other]`, custom values already set could be
Instead start with an empty [:other] hash which the component handles
correctly, then append to it as required.