core statistics: migrate view count

Problem/Motivation

core statistics is deprecated as of 10.3. Users that come to visitors will want to keep tier view count.

Steps to reproduce

Proposed resolution

If the core statistic module is installed, show a link to a form on the status report. If the user confirms, visitor's node view counts will be cleared, replace the count from core statistic, and then uninstall core statistic.

Remaining tasks

User interface changes

API changes

Data model changes