optimized d3 v4 with a custom made bundle

app/assets/javascripts/common_d3/index.js

...ssets/javascripts/graphs/stat_graph_contributors_graph.js

app/assets/javascripts/monitoring/components/graph.vue

...sets/javascripts/monitoring/utils/date_time_formatters.js

...sets/javascripts/monitoring/utils/multiple_time_series.js

app/assets/javascripts/users/activity_calendar.js

config/webpack.config.js

package.json

.../javascripts/graphs/stat_graph_contributors_graph_spec.js

yarn.lock