Improve column labels on the consensus review page and add informational message on the Internal Comments tab

All of the changes can be seen in this screenshot:

There are four primary changes here:

• The labels for Mean, Std.Dev and SRP Score now have help text explaining their meaning
• An informative message was added to the "Internal Comments" tab
• A trivial compiler warning was addressed in the consensus-reviews component
• A minor formatting snafu involving the edit icon on the SRP Score column was fixed, so the labels are now properly aligned

Some additional tooltips were added in a few other places during review.