Upload custom receive hook script file in repository setting

[birddevelper]

Hi!

It would be great if user could upload a custom hook script file in receive section. Because, in modern architectures, Gitblit may be deployed as docker container in local/cloud Kubernetes where modifying hook script files can be a difficult task.

So, by adding a upload feature, people can create or modify their own script file locally and upload them to be placed in data\groovy directory of Gitblit, then it appears in available scripts list.

Something like below image :