Implement escaping of webhook params

[416rehman]

When serving webhooks with user provided data, such as the deploy webhook, we want the received webhook parameters to be properly escaped.

This can be done by providing each argument to the printf utility with a '%q' specifier.

printf %q "$ARG1"

This will print a properly escaped value of $ARG1 by escaping all special characters such as quotes, slashes, etc in the $ARG1 variable.

The webhook image we are running is a based on Alpine and does not contain most GNU tools, therefore the printf utility in the image does not support %q specifier.

https://www.shellcheck.net/wiki/SC3050

The webhook/hooks directory contains scripts for all the webhooks, it also houses utility scripts, prefixed with a . such as .authenticate.sh, consider creating a .escape.sh script to achieve the functionality of printf %q to be used in the webhook scripts.