Jenkins reduce number of builds kept (10 -> 5)

.ci/Jenkinsfile-SITL_tests

@@ -201,7 +201,7 @@ pipeline {
   }
 
   options {
-    buildDiscarder(logRotator(numToKeepStr: '10', artifactDaysToKeepStr: '30'))
+    buildDiscarder(logRotator(numToKeepStr: '5', artifactDaysToKeepStr: '30'))
     timeout(time: 60, unit: 'MINUTES')
   }
 } // pipeline

.ci/Jenkinsfile-compile

@@ -158,7 +158,7 @@ pipeline {
     CI = true
   }
   options {
-    buildDiscarder(logRotator(numToKeepStr: '10', artifactDaysToKeepStr: '30'))
+    buildDiscarder(logRotator(numToKeepStr: '5', artifactDaysToKeepStr: '30'))
     timeout(time: 60, unit: 'MINUTES')
   }
 }

.ci/Jenkinsfile-hardware

@@ -140,7 +140,7 @@ pipeline {
     CI = true
   }
   options {
-    buildDiscarder(logRotator(numToKeepStr: '10', artifactDaysToKeepStr: '30'))
+    buildDiscarder(logRotator(numToKeepStr: '5', artifactDaysToKeepStr: '30'))
     timeout(time: 60, unit: 'MINUTES')
   }
 }

Jenkinsfile

@@ -501,7 +501,7 @@ pipeline {
     GIT_COMMITTER_NAME = "PX4BuildBot"
   }
   options {
-    buildDiscarder(logRotator(numToKeepStr: '10', artifactDaysToKeepStr: '30'))
+    buildDiscarder(logRotator(numToKeepStr: '5', artifactDaysToKeepStr: '30'))
     timeout(time: 60, unit: 'MINUTES')
   }
 }