Inline Block Title Automatic

Block content entities in layout builder suffer from a minor UI headache with regards to titles. All block content entities require the "info" field to have a value. In the reusable library world, this is labelled "Block description". This is surfaced in the admin UIs when searching through the block library as the administrative label of the entity, thus it is far useful to have a descriptive label such as "winter recycling campaign 2018" than something editorial such as "Recycle now!". These block descriptions are also required for any component that may not have a clear "title" element to display.

For inline blocks and reusable blocks, a "placement" label is also always required. For reusable blocks, this placement handily defaults to the "info" field described above, but can be changed! For inline blocks, this is mandatory and is used to populate the info field when a block is created, thus the placement label always equals the "info" label.

Allowing the placement label of the block to be overridden for reusable blocks and having it required for inline blocks is confusing. For reusable blocks, it breaks the model that content is authored in the block library, for inline blocks it's not clear if that content is actually designed to surface for end users (content admins would have to be aware of this and make that decision for every block they place).

This module fixes it by simply hiding all "placement" titles when inserting a layout builder block_content block and removing the "Title display" checkbox. As a result, a confusing decision is taken away from content authors.

The primary implication for site builders is: any primary user-facing title based component requires a new field and the "Block description" field should be purely used as an admin-facing description.