Remove travis build job (reproducer) and replace badge with Jenkins build status

[tfr42]

• [x] Remove http://buildserver.deegree.org/view/Failing%20Jobs/job/internal/job/travisci-build/
• [x] remove travis-ci pipeline from project
• [x] Install embeddable-build-status-plugin for Jenkins
• [x] Replace the badge for current build status in README.md
• [ ] Remove https://github.com/deegree/deegree3/tree/master/.github/workflows
• [ ] disable GitHub workflows

[tfr42]

Job is deactivated http://buildserver.deegree.org/view/Failing%20Jobs/job/internal/job/travisci-build/

[tfr42]

Build status plugin installed for Jenkins http://buildserver.deegree.org/job/deegree-3.4-master/badge/

[tfr42]

Changes to README.md in https://github.com/deegree/deegree3/pull/1082

[tfr42]

PR #1179 is merged

[tfr42]

The new server infrastructure #1130 is up and running, including recent Jenkins version building all PR https://buildserver.deegree.org/view/misc/job/deegree-3.4/job/pull-request/view/change-requests/