UI/API changes

• CHANGE: Defaults to one-off and 50 probes in measurement form
• CHANGE: Add use_macros option to DNS options in measurement form
• CHANGE: "Ongoing" in measurement (not status) references to "Periodic"
• FIX: double AS label in measurement form
• FIX: "Measurement created" banner not showing on second msm creation in measurement form
• FIX: Anchors list filter
• TWEAK: Formatting in various lists
• TWEAK: labels and naming on blank lists