move things to enterprise guide and add some images

docs/enterprise-guide/customizing-drill-through.md

.../images/customizing-drill-through/chart-link-template.png

...uide/images/customizing-drill-through/column-settings.png

...ges/customizing-drill-through/dashboard-link-template.png

...ide/images/customizing-drill-through/detail-dashboard.png

...guide/images/customizing-drill-through/example-charts.png

...se-guide/images/customizing-drill-through/link-option.png

...images/customizing-drill-through/table-options-filled.png

docs/users-guide/15-alerts.md