Use semantic HTML tags

[SaptakS]

There are few items which I feel can benefit from better HTML tags. Ideally we can maybe update the CSS to be applied on tag instead of a class in the design system if there is a fixed style for the elements, but I don't mind keeping the designs in class instead of HTML tags. Some elements I noticed:

• Highlighted text: Let's use <mark> for anywhere we are using highlighted text.
• Striked out text: Let's use <s> for striked out text, e.g. prices
• <div role="main"> : Let's replace this with <main>