After tested the plugin to compile against different Jenkins core versions, I have detected some changes that I have to make to test it.

• Update Jenkins file to compile an test on Jenkins core 2.150.1, 2.164.1, and 2.168 (2 LTS and last weekly)
• Compile and test weekly with JDK 11
• Upgrade Jenkins core to 2.150.1, I will support 2 LTS versions
• Remove JDKInstaller references, is not used in ssh-slaves and it is no longer in Jenkins core, it is in tool-jdk plugin
• Remove deprecated constructors, all these constructors were marked with a warning in logs 6 months ago.
• Remove unused code
• Remove old fields related to deprecated constructors
• Fix tests after changes
• Remove deprecated package dependency javax.xml.bind
• fix Inconsistent synchronization of hudson.plugins.sshslaves.SSHLauncher.host