Initialise Github Workflows

[Parthiv-M]

This patch adds the following:

• a scripts directory with a build.sh to handle building the patched OS images
• Separate Github Workflows to build and release the generated OS images

[DeveshChande]

As per my understanding, I believe the following modifications may prove to be helpful:

• On line 47, I think the condition should check for VAULTSLENGTH instead of VAULTLINUXOSES? If so, line 48 would have to be modified as well.
• Perhaps a redundant check since we are operating on GitHub, but would incorporating for the presence of the git package be a good error handling enhancement?
• Validating that the ISO has downloaded successfully before extracting (Link rot is real lol).

Please correct me if I am wrong.