Problem/Motivation
As discovered in #2820848-64: [PP-3] Add a publishing status field to BlockContent, Content Translation metadata fields ('content_translation_source', 'content_translation_outdated', 'content_translation_status') do not use an initial value for entities that exist prior to enabling CT on an entity type.
This poses a problem if anyone needs to rely on that data for example when making an entity type publishable by adding a 'real' status field.
Proposed resolution
Make CT use an initial value (#2346019: [PP-1] Handle initial values when creating a new field storage definition) for those fields and fix existing inaccurate data.
Remaining tasks
Write tests.
Review.
User interface changes
Nope.
API changes
Nope.
Data model changes
Nope.