cmd: Load config from the common config loader in hugolib
cmd: Load config from the common config loader in hugolib

See #2309

anthonyfok/hugo,jygastaud/hugo,mayah/hugo,MarkDBlackwell/hugo,fedelibre/hugo,MarkDBlackwell/hugo,bogem/hugo,anthonyfok/hugo,mdhender/hugo,tubo028/hugo,fedelibre/hugo,mitchchn/hugo,bogem/hugo,Zenithar/hugo,fedelibre/hugo,Zenithar/hugo,gohugoio/hugo,mdhender/hugo,tubo028/hugo,jygastaud/hugo,mdhender/hugo,gohugoio/hugo,mdhender/hugo,anthonyfok/hugo,digitalcraftsman/hugo,gohugoio/hugo,mitchchn/hugo,mayah/hugo,fedelibre/hugo,digitalcraftsman/hugo