Adapting webpack config to use webpack-configurator plugin method (#626)
Adapting webpack config to use webpack-configurator plugin method (#626)

simplifying plugin calls

reusing common plugin definition
danielfarrell/gatsby,chiedo/gatsby,mickeyreiss/gatsby,gatsbyjs/gatsby,mickeyreiss/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,okcoker/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,fabrictech/gatsby,chiedo/gatsby,Khaledgarbaya/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,chiedo/gatsby,fk/gatsby,gatsbyjs/gatsby,danielfarrell/gatsby,fk/gatsby,gatsbyjs/gatsby,fk/gatsby,danielfarrell/gatsby,Khaledgarbaya/gatsby,0x80/gatsby,Khaledgarbaya/gatsby,fabrictech/gatsby,0x80/gatsby,okcoker/gatsby,okcoker/gatsby,ChristopherBiscardi/gatsby,mickeyreiss/gatsby,fabrictech/gatsby,mingaldrichgan/gatsby,mingaldrichgan/gatsby