add JavaScript linting to CI (!5445)
add JavaScript linting to CI (!5445)

darkrasid/gitlabhq,iiet/iiet-git,iiet/iiet-git,dreampet/gitlab,openwide-java/gitlabhq,stoplightio/gitlabhq,htve/GitlabForChinese,LUMC/gitlabhq,openwide-java/gitlabhq,darkrasid/gitlabhq,stoplightio/gitlabhq,htve/GitlabForChinese,iiet/iiet-git,daiyu/gitlab-zh,iiet/iiet-git,axilleas/gitlabhq,mmkassem/gitlabhq,LUMC/gitlabhq,daiyu/gitlab-zh,dplarson/gitlabhq,dreampet/gitlab,dplarson/gitlabhq,axilleas/gitlabhq,htve/GitlabForChinese,t-zuehlsdorff/gitlabhq,t-zuehlsdorff/gitlabhq,darkrasid/gitlabhq,stoplightio/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,darkrasid/gitlabhq,openwide-java/gitlabhq,LUMC/gitlabhq,LUMC/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,mmkassem/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,dplarson/gitlabhq,dreampet/gitlab,openwide-java/gitlabhq,t-zuehlsdorff/gitlabhq,jirutka/gitlabhq,htve/GitlabForChinese,jirutka/gitlabhq,daiyu/gitlab-zh,daiyu/gitlab-zh,stoplightio/gitlabhq,jirutka/gitlabhq