Support different themes

[johnrees]

Support logo and theme colours for the following local authorities please!

• https://www.southwark.gov.uk
• https://www.buckinghamshire.gov.uk
• https://www.canterbury.gov.uk
• https://www.lambeth.gov.uk
• https://www.camden.gov.uk
• https://lewisham.gov.uk
• https://www.northumberland.gov.uk

[johnrees]

@houbly if you just want to support a single alternative theme for now that'll be ok. It'll mean that the site is prepared for when we connect the API and are able load the theme configuration json and logo urls dynamically.

So the other main tasks here are picking an appropriate background and text colour and downloading the logos (white svg if possible).

There are quite a few teams in this list now 🎉 if you want some help to get it done quicker @amirasalah or @Alastairparvin might be able to give you a hand.

Thanks!