LONDON/OSLO (Reuters) - British shale gas company Cuadrilla said on Thursday it would restart fracking at its Preston New Road site in Britain in the third quarter of 2019 and plans to use a thicker fracking fluid to help reduce earth tremors.Fracking, or hydraulically fracturing, involves extracting gas from rocks by breaking them up with water and chemicals at high pressure.Operations at the first well at the Preston New road site in Lancashire where halted several times last year because of..