[docs] update package, features and config mode docs #799

	# Based on the example from https://docs.github.com/en/actions/publishing-packages/publishing-docker-images
	name: Create and publish a Docker image

	on:
	push:
	branches:
	- 'main'
	- 'next'
	- 'v202[0-9].[0-9].x'
	tags:
	- 'v*'
	pull_request:

	env:
	REGISTRY: ghcr.io
	IMAGE_NAME: ${{ github.repository }}-build

	jobs:
	build-and-push-image:
	runs-on: ubuntu-22.04
	permissions: write-all
	steps:
	- name: Checkout repository
	uses: actions/checkout@v4
	- name: Set up QEMU
	uses: docker/setup-qemu-action@v3
	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v3
	- name: Log in to the Container registry
	uses: docker/login-action@0d4c9c5ea7693da7b068278f7b52bda2a190a446
	if: ${{ github.repository_owner == 'freifunk-gluon' && github.event_name == 'push' }}
	with:
	registry: ${{ env.REGISTRY }}
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}
	- name: Extract metadata (tags, labels) for Docker
	id: meta
	uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81
	with:
	images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
	- name: Build and push Docker image
	uses: docker/build-push-action@15560696de535e4014efeff63c48f16952e52dd1
	with:
	context: ./contrib/docker
	push: ${{ github.repository_owner == 'freifunk-gluon' && github.event_name == 'push' }}
	platforms: linux/amd64,linux/arm64
	tags: ${{ steps.meta.outputs.tags }}
	labels: ${{ steps.meta.outputs.labels }}

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