You can add the above search widget to a Moodle page via any text editor:
Click the down arrow in the far left corner 
and then select the html editor view button: 
Cut and paste in the following html:
<script type="text/javascript" src="//mhu.summon.serialssolutions.com/widgets/box.js"></script><script type="text/javascript">summonWidget.box({"id":"s55fa0ed0a89e679bbd6af47bd0ef2c1","endpoint":"//mhu.summon.serialssolutions.com","style":{"tagline":"#000","links":"#000"},"params":{"pn":1,"ho":true,"myinst":"","jt":"","l":"en"},"tagline_text":"Easily discover the world of library content","searchbutton_text":"Search","advanced_text":"More search options","placeholder_text":"","advanced":true,"suggest":true,"tagline":true,"popup":true})</script>