GitLab

This will improve performance as currently bots are fetching contents
from /changes which contains JSON data of patches, diffs as files and
archives which are generated on the fly, really nothing of relevance
to search engines.

https://github.com/NeoBlack/T3Bot/issues/16

- added support of TYPO3-theme for dark-mode
- smaller TYPO3 logo in login screen
- improved SVG of logo

* log hook name and arguments once per hook
* add newline after each hook file execution
* fix shellcheck issues
* remove extra logging in update-forge-issue hook

Removed no longer needed hosts and added gitlab.typo3.org

directory is mounted as docker volume

to avoid port collision when running git.typo3.org container in
development

- Use absolute paths
- Remove volumes
- Ignore all /.local/share/ contents

... as container names may differ

Port 8080 only has to be accessible internally as it is forwarded by the
nginx proxy.

Add files from opsone infrastructure to .gitignore and dummy for adapting
nginx configuration

In order to ease upgrades the optional declaration of the JRE/JDK
installation to use is removed:

https://gerrit-review.googlesource.com/Documentation/config-gerrit.html#container.javaHome

Switch to named volumes for cache, db, git, index and logs in order to
improve future compatibility with cloud services like Kubernetes. Move
etc and ssh from volumes to assets as they shall be versioned but
Gerrit may change contents. This means in future extra care has to be
taken when executing docker-build as changed contents inside the
container will be discarded.