Docker image creation

[chris3081]

This change build a docker image containing the dishorde bot.

Includes github workflow, only requires you to create a Private github token and place it in the secrets named DEPLOY_TOKEN.

Github Container Registry will be free for this image so the cost to maintain is only time.

[LakeYS]

Looks great for folks that use Docker. I'll give this a test soon. A couple of general questions:

• Any particular reason the gallium-bullseye-slim image is used here as opposed to an LTS variant? I try to stick to the LTS releases unless something specific is needed.
• Would you know on-hand if many people run the game itself using Docker? If so, I'd love to look at making a (separate) image that sets up the game and bot in one package. Docker's networking could be ideal for setting up the telnet connection with no-hassle. (i.e. vinanrra/7dtd-server)

[chris3081]

I'll have a look at switching to an lts image.

In my repos I maintain a portainer template json and stacks config for 7days for my own servers, your welcome to use anything you find there. https://github.com/chris3081/portainer-app-templates

For 7 days I use this one https://github.com/vinanrra/Docker-7DaysToDie

[LakeYS]

Hey there! If you're still here, do you mind if I push some changes? I'd like to tweak this a bit and merge it in. If I push changes, they will go to your master branch.

Here's what I'd like to do with it (no action required on your part)

• Use a LTS Alpine image for Node.js if possible.
• Test the GitHub workflow
• Expand the environment variables so that the rest of the options can be configured - For this, I might just modify the bot to accept environment variables in lieu of a config file.

Great work on this again and I appreciate the PR!