Finish the Views integration

Problem/Motivation

Initial views integration was written in #2927169: Fix views queries → , now we need to ensure that everything works properly, including $query->orderby, $query->groupby, $query->having and $query->count_field.

We also need to add more test coverage, as described in #2927169-2: Fix views queries → .

Another thing to check is this review point from @plach in #2784921-146: Add Workspaces experimental module → .39:

+++ b/core/modules/workspace/src/ViewsQueryAlter.php
@@ -0,0 +1,423 @@
+    // If the table was already added and has a join against the same field on
+    // the revision table, reuse that rather than adding a new join.

I can't be sure by just looking at the code, but it seems to me that this may not support the case where we are joining on the same entity type base/data table multiple times. Am I wrong or do we need to add a follow-up to support that as well?
multiple joins/aliases?

Proposed resolution

TBD.

Remaining tasks

TBD.

User interface changes

Nope.

API changes

Nope.

Data model changes

Nope.