As an Admin I'd like to see unexpected errors thrown by plugins while configuring them so that I can now that the plugin doesn't work or it has bugs

Acceptance Criteria:

• If while saving a plugin configuration unexpected errors happen, these errors should be shown as a red popup (see example in attachments) at the top of the page with the body of the error (exception message)
• Given the error occurred, it should be also logged in the app logs
• Given an unexpected error happened, plugin configuration should not get saved into database if error happened.
• Given the error is too long to fit the red area max height, a scrollbar should appear
• Given the error is too wide to fit the red area max width, a horizontal scrollbar should appear
• Given the error is couple of lines long, the red area should get shrinked to be the same size
• Given I clicked somewhere outside of the red area, it should not get closed
• Given I'd like to close the popup, I click on Close button at the top right corner.
• Given I'd like to see what's behind the red area (my input fields) I can drag the popup

@QA: right now since we do not have validation for plugins, all validation errors will be considered as unexpected. For instance if you put too much of text into input fields.