You could point each Juicebox gallery created by svManager towards the master 'jbcore' folder by editing the 'svmanager/plugins/juicebox/jbmaster/index.php' file in a plain text editor and changing line 27 from:
<script src="jbcore/juicebox.js"></script>... to:
<script src="http://www.example.com/svmanager/plugins/juicebox/jbmaster/jbcore/juicebox.js"></script>... changing 'www.example.com' in the example above to your own domain name.
The 'jbcore' folders in each gallery folder would then become redundant (though deleting them may have unwanted knock-on effects within the svManager admin area which expects the folders to be there).
Please note that the line number refers to svManager v1.8.3.
If creating your Juicebox galleries with Lightroom and importing them into svManager, you would need to manually alter the path to the 'juicebox.js' file (in each gallery's 'index.html' file) to point to the master 'jbcore' folder within your svManager installation. However, by doing so, you would be unable to view the gallery locally and it would function only when uploaded to your web server.