title: Center plotly title by default
body: <p>I have a plotly figure which I center the title using -</p>
  <pre><code>fig.update_layout(
              title={
              'text' : title,
              'x':0.5,
              'xanchor': 'center'
          })
  </code></pre>
  <p>I have multiple graphs and I add this to every one of them. I wonder if I can define it in advance, e.g using config object or settings, and not do it for every chart.</p>