Submitters Must Submit All Files Up Front

## The issue
the iMS portal expects users to submit all files in one submission up front, however, this is expectation is unclear to users, as there is no indication on the UI or documentation.

Nima had 20 samples, but not all of them have files in the first submission, he submitted 3 files, committed it. When he went back and wanted to submit more files, the portal did not allow it. This was confusing to him as there was no instruction or clarification in the portal.

This issue is somewhat relevant: https://github.com/imicroseq/task-tracking/issues/39

## The solution
@justincorrigible and @leoraba to propose a solution.
one idea: adding a modal on the commit button to let users know that this is the final submission