Drop support for Field Collection

Problem/Motivation

Field collection has dropped support for their Drupal 8 branch, since it superseded by Paragraphs. Full discussion at #2784931: Proposal: Deprecate Field Collections for Drupal 8, focus on Entity Reference Revisions & Paragraphs.

Proposed resolution

As stated, users are encouraged to move to paragraphs; support for field collection fields are to be dropped.

Remaining tasks

• Add deprecation notice to 8.x-1.x.
• Remove the field collection integration code.
• Remove any tests related to field collection.
• Add change notice.

User interface changes

There would no longer be a Table of Fields formatter option for field collections.

API changes

Removal of the \Drupal\reference_table_formatter\Plugin\Field\FieldFormatter\FieldCollection class.