Timepicker disabled in Timelion/TSVB when default index has no timefield

[timroes]

If the default index pattern stored in Kibana is not having an time field configured, the time picker will be disabled in TSVB and Timelion, since the editor will look for the default index pattern in those editors (like Timelion and TSVB) that don't specify any index pattern (e.g. because they can use multiple). Especially for time based data it's of course important to select a time range, so the timepicker should be enabled for those applications by default.

We already have a showTimePicker setting in vis, that we use only for disabling the time picker (in markdown), but we could also make sure we leverage that setting in case the visualization doesn't specify an index pattern to check if we want to show the timepicker in those cases or not.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)