support redelivering a webhook

[jbrockopp]

Description

Earlier this year, GitHub introduced support for API functionality for webhooks:

https://github.blog/changelog/2021-06-30-webhook-deliveries-api/

We should add support to Vela to be able to redeliver a webhook:

https://docs.github.com/en/rest/reference/webhooks#redeliver-a-delivery-for-a-repository-webhook

This functionality could, and possibly should, be replicated from the existing logic used to restart a build:

https://go-vela.github.io/docs/reference/api/build/restart/
https://go-vela.github.io/docs/reference/cli/build/restart/
https://github.com/go-vela/server/blob/master/api/build.go#L745

Value

• improve the user experience when a user needs to redeliver an existing webhook

This can happen for multiple reasons but to provide a quick example:

• an admin of a repository from the source system enables that repository in Vela
• this user becomes the "owner" of that repository in Vela
• the user's account is deactivated or removed from the source system
• anytime a build is triggered they'll receive a 403 Your account has been suspended error message

To resolve this issue, it often requires a user to go and change ownership of the repository in Vela

After they perform that action, they are forced to redeliver any webhooks that failed with the 403 error manually

Instead, I propose they be able to redeliver the failed webhook through the Vela system

Definition of Done

A user can trigger some interaction through Vela that initiates an API call to the source system to redeliver a webhook

Ideally this would include an API endpoint, CLI command, and button in UI that enable this functionality

Effort (Optional)

1 week

Impacted Personas (Optional)

everyone

[ecrupper]

Started to take a look at this. It seems like Go-GitHub has yet to implement this on their end. I decided to open up a PR.