Consistent colour scheme for the website

[AlphaSheep]

The website is currently using an inconsistent mixture of colours taken from Bootstrap's defaults used in the original version of the website, and a few custom colours.

We should go through the colours used in the website and ensure the following:

1. All colours are reverenced from variables set in client/src/app/styles/variables.less. There should be no colours specified elsewhere.
2. A colour palette should be designed that represents CubingZA's brand, and South Africa in general.
3. The colours in client/src/app/styles/variables.less should be carefully chosen from the brand colour palette to give a consistent look-and-feel to the website.