* 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
We have received a lot of feedback regarding the ValueString in alert notifications. Perhaps one of the most frequent complaints about ValueString is that it is difficult to read because it contains a lot of information, and the information is shown as a JSON-like string. Users have often asked how it can be templated and the answer is that it can't.
Until now users have been able to add custom annotations to their alert rules which contains values via the $values variable added in previous versions of Grafana. However, these custom annotations must be added for each of the user's alert rule, instead of once in a template that all of their alerts can be notified via.
This commit adds then the much requested feature to support values in notification templates. Users can then create a single template that prints the annotations, labels and values of their alerts in a format of their choice!
