change registered devices activity to allow deleting old / unused CNL

app/build.gradle

app/src/main/AndroidManifest.xml

...o/nightscout/android/medtronic/GetHmacAndKeyActivity.java

.../java/info/nightscout/android/medtronic/MainActivity.java

.../info/nightscout/android/medtronic/ManageCNLActivity.java

.../android/medtronic/message/PumpStatusResponseMessage.java

app/src/main/res/layout/activity_login.xml

app/src/main/res/layout/activity_manage_cnl.xml

app/src/main/res/layout/activity_status.xml

app/src/main/res/layout/cnl_item.xml

app/src/main/res/layout/manage_cnl_listview_header.xml

app/src/main/res/values/strings.xml