Move gage selection button inside discharge input in Jobson's modal

[tgross-usgs]

Need to reduce space taken up in the top inputs of Jobson's modal. We should move the "Find Gages" button up into the discharge input box. See examples below.

I'm envisioning adding a right-hand section like in the calendar button below.

Instead of an icon in the button we want text. For now let's use "View gages" inside the button. The placeholder text will need to be shorter, maybe "Enter value or select gage". I'm sure we'll have more discussion on what exactly the text on these items should be. Open to suggestions. :-)