Improve Heading Structure of homepage

See CIDI review Recommendations #2 (closed)

Recommended:

<h1>GALILEO: Georgia's Virtual Library</h1>
<h2>Imagine. Discover. Explore.</h2>
<h2>Discover</h2>
<h3>Databases by Subject</h3>
<h3>Databases by Type</h3>
<h2>In the Spotlight</h2>
<h3>Article Card Heading</h3>
<h4>About "Institution Name"</h4>
<h4>GALILEO News</h4>
<h4>GALIEO System Alerts</h4>
<h2>About GALILEO</h2>
<h2>Programs</h2>
<h2>Governance</h2>
<h2>Community</h2>
<h2>Tools & Training</h2>
<h2>Support</h2>
<h2>Contact Us</h2>```