Add optional verbose output of entities to be created, updated or skipped

Problem/Motivation

The module currently only reports sums of what should be imported. In a development process you sometimes need detailed information.

Steps to reproduce

Proposed resolution

Leverage the --verbose option of drush and output details:

± drush dcdi --verbose
+--------+---------------+--------------------------------------+
| Action | Entity Type   | UUID                                 |
+--------+---------------+--------------------------------------+
| skip   | user          | 604bd4e1-710f-4823-949b-c00c5ac7b081 |
| skip   | file          | 403f38cf-5394-4616-b0d7-074aad207ffb |
| skip   | media         | 3b503dd1-0f03-444e-bca3-068d4cef6ccc |
| update | block_content | ef58a944-f383-4c53-91c9-2dee7522dca3 |
| skip   | file          | 42b49150-594b-436f-975a-3293e0fe6e7e |
| skip   | media         | af40a2ec-8a8d-4b0a-badf-ff591a54c394 |
| update | block_content | 65463548-d72c-4129-b432-afd65e82dab4 |
| update | block_content | 15db36ba-6090-4eca-af50-6f9d70809deb |
| skip   | file          | 0bcc9fe5-ce1f-4cca-b9d6-d540d5060162 |
| skip   | media         | 590e073f-3335-41ce-89f3-199148944a6e |
| update | block_content | 95e92864-3049-4c4c-9573-4224c0e85f4e |
| update | node          | 8877c312-e6a6-4913-b3de-9a086c89fd5b |
| update | node          | 81dfd72c-a164-4e16-b7e9-c538a5405c12 |
| update | node          | c6e1312c-e15e-4b4d-9bde-da8779735682 |
+--------+---------------+--------------------------------------+
Summary:
- created: 0
- updated: 7
- skipped: 7

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Remaining tasks

User interface changes

API changes

Data model changes