[enh] #918 Add external module support through WebUI

app/js/app.config.js

app/js/controllers/main/MainController.js

app/js/controllers/main/settings/tabs/ModulesController.js

app/js/lib/conf/i18n/en.json

app/js/lib/conf/routes.js

app/js/services/webmin.js

app/styles/main.styl

app/views/main/main.jade

app/views/main/settings/settings.jade

app/views/main/settings/tabs/modules.jade

cesium.js

index.js

misc/duniterConfigToCesium.js

package.json

public/app.css

public/app.css.map

public/app.js

public/app.js.map

public/templates.js

server/controller/webmin.js