Add support for sending response body in alert message

[arnasbr]

Describe the feature request

It would be nice to have a flag that would make Gatus send the response body together with the alert. A bonus would be setting a condition for it. For example, I only want to see the response body if response.status != 200.

This issue #709 sort of overlaps, but maybe implementing this flag would be quicker / easier than full on templating.

Why do you personally want this feature to be implemented?

It is very inconvenient seeing a non-200 response code, but not being able to see what error message came with it.

How long have you been using this project?

Over a month

Additional information

No response