Settings added

public/chart_utilities.js
   - showError with id

public/javascripts/global.js
   - save parameter fron settings

views/index.pug
    - add settings dialog

views/layout.pug
   - add flatpicker

public/javascripts/map.js
   - add error evaluation

public/javascripts/showcharts.js
   - error avelauation added

public/stylesheets/style.sass
   - add styles for settings dialog

public/javascripts/chart_utilities.js

@@ -179,7 +179,7 @@ export async function addSensorID2chart(chart, sensor, width) {
 }
 
 export const showError = (err) => {
-    document.querySelector('.modal-body').setHTML(err)
+    document.querySelector('#dialogError .modal-dialog .modal-content .modal-body').setHTML(err)
     let myModal = new bootstrap.Modal(document.getElementById('dialogError'))
     myModal.show()
 }