Update Sponsors section

[riteshsp2000]

A new design has been created for the sponsors' section.

• Implement the design using css-grids.
• Make sure the entire section is responsive and the order of sponsors as per the design.
• Abstract the section as much as possible so that it is not bound to a particular layout and is easily responsive.
• size of the logos starts decreasing from the top.
• Maintain the ratio for boxes of gamma and delta sponsors.
• instead of just 2 in a row for delta, possibly have 3. the gamma box should be flexible and the number of sponsors in a row should adjust as per the width.
• For mobile view, it should be one below the other.

[padmajabhol]

Interested.