docker: remove misleading comments, fix gz ending

The files must be run through the Flake (script) now.
Nixpkgs builds tar.gz, our filename was wrong.

flake.nix

@@ -120,14 +120,14 @@
                   echo "Tested with VSCode, Pycharm."
                 '';
                 build_docker_app.exec = ''
-                  out=docker-image-ekklesia-portal.tar
+                  out=docker-image-ekklesia-portal.tar.gz
                   nix build .#docker -o $out
                   echo "Built container image for the application".
                   echo "Load the image with:"
                   echo "docker load -i $out"
                 '';
                 build_docker_static.exec = ''
-                  out=docker-image-ekklesia-portal-static.tar
+                  out=docker-image-ekklesia-portal-static.tar.gz
                   nix build .#dockerStatic -o $out
                   echo "Built container image for the static files (assets)".
                   echo "Load the image with:"

nix/docker.nix

@@ -1,10 +1,3 @@
-#!/usr/bin/env -S nix-build -o docker-image-ekklesia-portal.tar
-# Run this file: ./docker.nix
-# It creates a docker image archive called docker-image-ekklesia-portal.tar.
-# Default tag is the git version. You can set a custom tag with:
-# ./docker.nix --argstr tag mytag
-# Import into docker with:
-# docker load -i docker-image-ekklesia-portal.tar
 { pkgs, serveApp }:
 
 let
@@ -17,6 +10,7 @@ in
 pkgs.dockerTools.buildLayeredImage {
   name = "ekklesia-portal";
   contents = [ passwd ];
+
   config = {
     ExposedPorts = { "8080/tcp" = { }; };
     User = user;

nix/docker_static.nix

@@ -1,10 +1,3 @@
-#!/usr/bin/env -S nix-build -o docker-image-ekklesia-portal-static.tar
-# Run this file: ./docker_static.nix.
-# Default tag is the git version. You can set a custom tag with:
-# ./docker_static.nix --argstr tag mytag
-# It creates a docker image archive called docker-image-ekklesia-portal-static.tar.
-# Import into docker with:
-# docker load -i docker-image-ekklesia-portal-static.tar
 { pkgs, serveStatic }:
 
 let