Switch from config file to environment variables

[LeoColomb]

While environment variables are not perfect, they are quite easier to manage in a Kubernetes context than a config map, especially for few options.
In that way, the surface of failure is substantially reduced (no file, no description scheme, no runtime dependencies, etc.), and are more intuitive to configure per deployment.

The host private key is still a secret, mounted as a volume to embrace the best security recommendations.

[Kooper]

I have nothing to object with, lets stick to environment variables for the server configuration to not bother users with config maps

[LeoColomb]

@Kooper Thanks for merging! 🥳
Would it be possible to create a git tag on the repository? The version that fits you the best, e.g., v0.1.0
I expect the GoReleaser action to then push the release notes and the Docker image.

[Kooper]

Well, @LeoColomb, thanks for your contributions! I think the improvements you made are deserving a release, so I'm tagging the proposed version with the alpha pre-release version.
I've generated the default description for now

[Kooper]

BTW the release pipeline has been failed with the "error=docker images: failed to publish artifacts: failed to push ghcr.io/kooper/ingressh:v0.1.0-alpha after 0 tries: failed to push ghcr.io/kooper/ingressh:v0.1.0-alpha: exit status 1: unauthorized: unauthenticated: User cannot be authenticated with the token provided."

So I think I should somehow setup access token to write to ghcr.io 🤔
UPD It looks like package must first be connected with the code repository. However I'm unable to find any control to create a package in the GH interface yet

[LeoColomb]

So I think I should somehow setup access token to write to ghcr.io

Oy, no, it's me again forgetting the basics. Let me submit another PR.