Replace image references with online ressources so they still display on DockerHub

.gitlab/.readme_variables

 export GITHUB_REPONAME='docker-D-Zone'
 export GITHUB_USERNAME='Griefed'
-export GITHUB_REPONAME_HEADER='docker-D-Zone_header.png'
-export GITHUB_REPONAME_SCREENSHOT='docker-D-Zone_screenshot.png'
+export GITHUB_REPONAME_HEADER='https://i.griefed.de/images/2020/11/18/docker-D-Zone_header.png'
+export GITHUB_REPONAME_SCREENSHOT='https://i.griefed.de/images/2020/11/18/docker-D-Zone_screenshot.png'
 export DOCKERHUB_REPONAME='d-zone'
 export DOCKERHUB_TAG_ONE='port'
 export DOCKERHUB_TAG_TWO='proxy'

.gitlab/readme_template

-[![$GITHUB_REPONAME](img/$GITHUB_REPONAME_HEADER)](https://github.com/$GITHUB_USERNAME/$GITHUB_REPONAME)
+[![$GITHUB_REPONAME]($GITHUB_REPONAME_HEADER)](https://github.com/$GITHUB_USERNAME/$GITHUB_REPONAME)
 
 ---
 
@@ -13,7 +13,7 @@ $GITHUB_REPONAME
 
 $DESCRIPTION
 
-[![$CREATOR_REPONAME](img/$GITHUB_REPONAME_SCREENSHOT)](https://github.com/$CREATOR_USERNAME/$CREATOR_REPONAME)
+[![$CREATOR_REPONAME]($GITHUB_REPONAME_SCREENSHOT)](https://github.com/$CREATOR_USERNAME/$CREATOR_REPONAME)
 
 ---
 

README.md

-[![docker-D-Zone](img/docker-D-Zone_header.png)](https://github.com/d-zone-org/d-zone)
+[![docker-D-Zone](img/docker-D-Zone_header.png)](https://github.com/Griefed/docker-D-Zone)
 
 ---
 
@@ -19,7 +19,7 @@ D-Zone is a graphical simulation meant to abstractly represent the activity in y
 
 Creates a Container which runs [d-zone-org's](https://github.com/d-zone-org) [d-zone](https://github.com/d-zone-org/d-zone), with [lsiobase/alpine](https://hub.docker.com/r/lsiobase/alpine) as the base image, as seen on https://pixelatomy.com/dzone/?s=default.
 
-The lsiobase/alpine image is a custom base image built with [Alpine linux](https://alpinelinux.org/) and [S6 overlay](https://github.com/just-containers/s6-overlay).
+The [lsiobase/alpine](https://hub.docker.com/r/lsiobase/alpine) image is a custom base image built with [Alpine linux](https://alpinelinux.org/) and [S6 overlay](https://github.com/just-containers/s6-overlay).
 Using this image allows us to use the same user/group ids in the container as on the host, making file transfers much easier
 
 ## Deployment