add dynamic date range calculation for dates, and add color gradient component, add color gradient for language and chrono
<div class="notice">
<div class="notice-header">
<h2>Notice</h2>
</div>
<div class="notice-body">
<p><b>Titre </b>{{model.title}}</p>
<p><b>Langue </b>{{#each model.languages as |lang index|}}{{if index ", "}}{{doc-language url=lang}}{{/each}}</p>
<p><b>Enregistré le </b>{{model.modified}}</p>
<p><b>Interviewer </b>{{model.publishers_disp}}</p>
<p><b>Description </b>{{model.description}}</p>
<p><b>Type de Discours </b>{{model.type}}</p>
<p><b>Localisation </b>{{model.spatial}}</p>
</div>
</div>