Update Getting Started

# Description
We need to build a new version of the Bounties Network [getting started page](https://bounties.network/gettingStarted.html)!

Here is a picture of the design itself:
*Desktop:*

Here is a zip folder of the various SVG files found in the design:

[gettingstarted.zip](https://github.com/Bounties-Network/bounties.network/files/2435872/gettingstarted.zip)

This new site should follow the attached design as closely as possible, and should reuse as many elements (css, HTML) from the new site that's found on the `new-design` branch of this repo

# Requirements
A correct submission for this bounty will:
- BE RESPONSIVE : it should either follow the above design to the letter, or should adjust the visual components to react to changes in screen sizes (i.e. mobile responsive)
- Use flexbox grid (fleboxgrid.com) to organize the visual components in a way that appropriately responds to changes in content or screen resolution
- Build off of the `new-design` branch, using all of the same methods for the new page as is used on the `index.html`
- Once you're finished, please open a PR to the `new-design` branch with your changes

# Revisions
We will require at most 4 revisions for submitted work, and expect whoever completes this bounty to come to us with intermediate questions (especially regarding mobile responsiveness) rather than making assumptions on one's own.