Updating home content (#49)

* change: skeleton of the HomePage html and inside content

* add: centerText class to style headings

* change: grid class to have a restricting width and center it

* change: styling for the HomePage

* add: Learn More button to HomePage and its styling

* change: the card box size to responsive in the HomePage and add hover effect to buttons

* change: hover state color to gray on the question cards, put a container on the bottom text and button instead of a <br /> element and style the learn more button element as well as make it function as a link to about-us page

* change: fix the button class width to 8rem

Author: manecipoglu