* Remove null values from JSON
* Specify the color field
* Add note about openness of custom field's struct
* Update schemaVersion
* Specify thresholds
* Add panel id
* Add maxDataPoints and interval
* Add mappings, albeit very under-specified
* Allow empty string for timezone field
This is probably not a good idea - same as allowing nulls.
* Allow false for refresh - otherwise, string
* Make threshold value optional
* Make interval optional
* Fix broken and changed decls in ui models
* Add models.cue for timeseries panel
* Fixups for home dashboard
* Add timeShift, timeFrom
* Abstract out #Target, rejigger comments