[#71587328] Defining variables to cancel a webhook

Defining variables to cancel sending a webhook
[#71587328] Implementing logic to cancel a webhook

Implementing resque logic to cancel a webhook from being sent.
[#71587328] Implementing webhook cancelation for non-team

Implementing logic to cancel a webhook if the group that triggered the
hook is not a team.
[#71587328] Adding send flag mutator methods

Adding mutator methods for the webhook send flag
[#71587328] Implementing send flag mutator methods

Implementing the webhook send flag mutator methods.