Provide shortcut for TQL Eval

[sunng87]

In some cases we use TQL Eval for promql query, it requires the time window tuple (start, end, step). Would be helpful if we have an widget to generate this tuple, for example "Last 5 minutes", "Last 1 hour". We can reuse the widget from our promql UI.

[sunchanglong]

the PromQL query do same thing, both use PromQL for query and return with same response format like sql.
user also need to familiar with PromQL to use TQL, so can user directly run the query in PromQL mode? add the widget in sql mode may make sql ui a bit complex

[sunng87]

Yes. Display it by default will be confusing. A better idea is to show this after user typing tql eval