Views support is back. Relocate relation.views.inc Cleaned up terminology in relation.views.inc. Left is now source, Right is now target.
Fixed warnings and css path on relation type edit form.
Unused plugin directory and file deleted.
Required 'type' key added to .info.yml files
Issue #1945294 by naught101, mikran: Fixed Minimum & maximum arity settings are not properly validated.
Issue #1977672 by naught101: stub-fix: display targets of directional relations in dummy field.
Coding Style. Issue #[1987056] by naught101: Convert line endings to Unix and other coding style.
Plugin no longer required
General coder-review cleanup
relation_create/save validation tests
