remove jenkins build history of everyjob code example

Example: jenkins delete all builds of a job

def jobName = "KPI_Measurements/KPI_Build_delete/KPI_delete_build"  
def job = Jenkins.getInstance().getItemByFullName(jobName, Job.class)
job.getBuilds().each { it.delete() }  
job.nextBuildNumber = 1   
job.save()