Support custom field queries for Test Pilot Snooze Tabs experiment about ping-centre HOT 1 CLOSED

The ideal way to do this is introducing a new ping-centre topic for SnoozeTabs, which includes following steps:

• Choosing a new topic other than reusing "testpilot", e.g. "snooze_tabs" (by client)
• Defining the new schema with new fields "snooze_time" and "snooze_time_type" (by client)
• Creating a new table and ETL job to load the pings into Redshift (by ping-centre)
• Generating basic dashboards on Redash (by ping-centre)

Note:

• We have to use a new topic as its pings will be loaded into a separate table
• As @6a68 mentioned earlier, we can just reuse the "testpilot" schema for convenience
• Once the new table gets created, we can reload the previous pings to the new one

from ping-centre.