Build Docker Hub images via Github Actions

Since docker hub stopped Autobuild, we need to switch to something else.
This will trigger building of images on Github Actions and pushes them
to Docker Hub.

You only need to add 3 secrets before you merge this PR to have it working directly.

- DOCKERHUB_USERNAME : The username of the account you are going to push the builds to
- DOCKERHUB_TOKEN : The token needed to login and push builds
- DOCKERHUB_REPO : The repo name in the following form `index.docker.io/<user>/<repo>`
  So for vaultwarden that would be `index.docker.io/vaultwarden/server`

Also some small modifications to the other workflows.

.github/workflows/hadolint.yml

@@ -2,11 +2,10 @@ name: Hadolint
 
 on:
   push:
-    # Ignore when there are only changes done too one of these paths
     paths:
       - "docker/**"
+
   pull_request:
-    # Ignore when there are only changes done too one of these paths
     paths:
       - "docker/**"
 
@@ -28,7 +27,7 @@ jobs:
           sudo curl -L https://github.com/hadolint/hadolint/releases/download/v${HADOLINT_VERSION}/hadolint-$(uname -s)-$(uname -m) -o /usr/local/bin/hadolint && \
           sudo chmod +x /usr/local/bin/hadolint
         env:
-          HADOLINT_VERSION: 2.6.1
+          HADOLINT_VERSION: 2.7.0
       # End Download hadolint
 
       # Test Dockerfiles