Update Jenkins core and plugin versions for jcasc template

[TT-S3-D1]

Describe the feature request

At the jcasc template, LTS version and plugin versions are outdated and the template should be again plug'n'play.

Upstream changes

• update LTS version hint
• check versions and compatibility for all referenced plugins
• prepare acceptance test and test pipeline at TraceTronic infrastructure
  • update GitHub status
• (optional) check auto update possibilities