fix IP address showing in View Data URL and homepage Share image

[nspmx]

Harcoded host value at NGINX level to map prod host as the used value at Virew Data component

ref:

• https://github.com/Datawheel/canon/blob/master/packages/cms/src/components/Viz/Options.jsx#L375
• https://github.com/Datawheel/canon/blob/master/packages/core/src/server.jsx#L52-L73