* adds modal for rendering the share url
* adds new custom_widget text-to-clipboard-input.html
* provides a copy button for writing the text input's value into the client's clipboard
* adds translation
* adds access_token as new attribute
* adds generating of access_token
* adds new form
* adds two new routes for sharing an intervention
* adds translation
* adds render_submit to BaseModalForm which triggers rendering the modal footer
* refactors templates/table.html into templates/generic_index.html
* adds DummyFilterInput as do-not-render-widget
* hardens combination of q filter and other filters on index view rendering
