Report config entity

Problem/Motivation

Visitors displays several views on diferent pages. It is possible to update the views, but changing the order or which reports appear on which page is impossible.

Steps to reproduce

Proposed resolution

Create a config entity that stores views in which row/column.

The report can define a path to display the report. They are all after /admin/visitors.

Reports can be created without a path.

Entities can also have a report located at: node/1/visitors, or whatever the entity.canonical is.

Remaining tasks

User interface changes

API changes

Data model changes