Optimise the image content

[pnpavlov]

As engineer maintaining the vulnerability database backend, I would like to have a minimal image that is optimized and has limited size and only relevant content.

• Optimise the Java runtime for the app by applying the concept of a separated build container in multi stage container build
• Optmise the Java runtime environment included in the final image via jlink. Example here use jlink to build a smaller image glvd-api#53
• Optimize the container image via unbase_oci tooling. glvd: deploy bare container image #128

[fwilhe]

Stats on space savings

full image (gardenlinux base, sapmachine 21 jre headless, glvd.jar) : 319 MB
bare image (sapmachine 21 jre headless, glvd.jar)                   : 235 MB
jlink+bare image (stripped down jre, glvd.jar)                      : 156 MB