Style anki text with HTML tag

[XSAM]

This PR adds HTML tags to the Anki text, so users can easily style their Anki cards by changing the Styling setting

Comparison of the back of the Anki card

Before

After (with #1142 and my custom CSS style)

.card {
    font-family: arial;
    font-size: 20px;
    text-align: center;
    color: black;
    background-color: white;
}

.back {
  text-align: left;
}

.explanation.trait {
  color: #5d2fc1
}

.explanation.explain.primary {
  font-weight: 700;
  font-size: 18px;
  color: #1d2a57;
}

.explanation.explain.secondary {
  font-size: 16px;
  color: #0580e8;
}

.sentence {
  color: #1d2a57;
  font-size: 17px;
}