* Add Preview template and payload editor to templates form
* Add TemplatePreview test and update css
* Preview errors for each template that is wrong
* Enable preview templating only for Grafana Alert Manager
* Use harcoded default payload instead of requesting it to the backend
* Update error response in the api definition
* Add spinner when loading result for preview
* Update api request followind DD changes
* Use pre instead of TextArea to render the preview
* Fix tests
* Add alert list editor
* Add start and end time for alert generator
* Add preview for data list added in the modal
* Update copies and move submit button in alert generator to the bottom
* Copy updates
* Refactor
* Use tab instead of button to preview
* Move payload editor next to the content
* Copy update
* Refactor
* Adress PR review comments
* Fix wrong json format throwing an exception when adding more data
* Use monaco editor for payload
* Only show text 'Preview for...' when we have more than one define
* Fix some errors
* Update CollapseSection style
* Add tooltip for the Payload info icon explaining the available list of alert data fields in preview
* Set payload as invalid if it's not an array
* Fix test
* Update text in AlertTemplateDataTable
* Add separators to distinguish lines that belong to the preview
* Fix text
* Use subDays instead of addDays for substracting days
