NGSTACK-458

[hknezevic]

• change the base Symfony form theme we are extending in the custom form theme from "form_div_layout" to "bootstrap_4_layout". We are using bootstrap 4 in the current website frontend.
• this also solves the visual/markup problem with rendering certain Symfony form fields on the frontend (checkboxes, radio buttons, date and date/time)
• remove form-control CSS class from all form_row elements, it is now added through the theme
• apply custom form theme in all templates where we render Symfony forms.

[emodric]

Thanks @hknezevic !