Update OCL Mapper toolbar buttons & icons

[paynejd]

General styling:

• Inactive state -- gray icon; no border
• On mouseover: highlight gray background (similar to google drive); make the corners more rounded

Project Toolbar

• Settings -- no change to icon except use the default gray; no change to tooltip; no label; move this to the right with the rest of the project toolbar
• Project History -- no change to icon, except use the default gray; tooltip "Project History"; no label
• Download -- no change to icon, except use the default gray; tooltip "Download"; no label
• Delete -- no change to icon, except use the default gray; tooltip "Delete mapping project"; no label

Candidates Toolbar

Left align:

• Filter: no change for now

Right align all of these:

• Refresh -- same icon, no label, no border; mouseover tooltip "Refresh Candidates" -- this will wipe out existing candidates AND existing AI Assistant recommendations (though everything is maintained in the log history)
• Group -- change icon to Layers; no label, no border; tooltip "Group By"
• Sort -- change icon to Sort; no label, no border; tooltip "Sort"
• AI Assistant -- same icon, remove border; reduce the left/right margins of the down-arrow a lot
• Display: No label; make this look like Google Drive, except toggle between List View (default) DensityMedium icon and Table View TableChart -- mouseover should say "List View" and "Table View"