Add report to list items that have active holds (and how many).

[jim]

What it does

Adds a new report that lists items with holds and how many holds they each have.

Why it is important

I think this is likely generally useful for folks to know what has the most holds. I wanted it to help keep an eye on the other hold changes that I rolled out as well.

UI Change Screenshot

Your bandwidth for additional changes to this PR

Please choose one of the following to help the project maintainers provide the appropriate level of support:

• I have the time and interest to make additional changes to this PR based on feedback.
• I am interested in feedback but don't need to make the changes myself.
• I don't have time or interest in making additional changes to this work.
• Other or not sure (please describe):

[phinze]

LGTM!