Allow user to add labels on left and right y-axis of data graphs

[damies13]

Is your feature request related to a problem? Please describe.
Currently a data graph displays numbers on the left and right y-axis when they are enabled, but there is no ability to give a label that mentions what the number represents (seconds, percent, etc)

Describe the solution you'd like
Allow user to add labels on left and right y-axis of data graphs, under the enable checkbox there should be a field for the y-axis label before the data type option