Add a 'Select All' option to the Matching Files Candidate Matcher selection process.

[mark-dce]

STORY
As a user uploading a batch of files and using template metadata, I would like to be able to select all results in the search set at once, so that I don't have to individually click on each matching file to add it to the batch.

ACCEPTANCE

1. There is a 'select all' option at the top of the list that selects all results on the page.