Display system information

[matthias-ronge]

In the „system“ part of the GUI, an „info“ tab should be added, that shows system information, like:

• Java version
• Tomcat version
• MySQL/MariaDB version
• ElasticSearch version
• ImageMagick version

and maybe other interesting information (like, is the metadata directory writable?)

Suggestion was to run a script in the background, that can check for various things (and may be locally configured, it may need sudo privileges for some checks) and the script output is displayed on the info page.

A mailto: link to send the information should be provided.