* Refactor Explore query field
- extract typeahead field that only contains logic for the typeahead
mechanics
- renamed QueryField to PromQueryField, a wrapper around TypeaheadField
that deals with Prometheus-specific concepts
- PromQueryField creates a promql typeahead by providing the handlers
for producing suggestions, and for applying suggestions
- The `refresher` promise is needed to trigger a render once an async
action in the wrapper returns.
This is prep work for a composable query field to be used by Explore, as
well as editors in datasource plugins.
* Added typeahead handling tests
- extracted context-to-suggestion logic to make it testable
- kept DOM-dependent parts in main onTypeahead funtion
* simplified error handling in explore query field
* Refactor query suggestions
- use monaco's suggestion types (roughly), see
https://github.com/Microsoft/monaco-editor/blob/f6fb545/monaco.d.ts#L4208
- suggest functions and metrics in empty field (ctrl+space)
- copy and expand prometheus function docs from prometheus datasource
(will be migrated back to the datasource in the future)
* Added prop and state types, removed unused cwrp
* Split up suggestion processing for code readability
* style header like other grafana components
* use panel container for graph and same styles for query field
* fix typeahead CSS selector (was created outside of .explore)
* use navbar buttons for +/- of rows
* moved elapsed time under run query button
* fix JS error on multiple timeseries being returned
* fix color for graph lines
* show prometheus query errors
* panel container menu gets new Explore entry (between Edit and Share)
* entry only shows if datasource has `supportsExplore` set to true (set
for Prometheus only for now)
* click on Explore entry changes url to `/explore/state` via location provider
* `state` is a JSON representation of the panel queries
* datasources implement `getExploreState()` how to turn a panel config into explore initial
state
* Explore can parse the state and initialize its query expressions
* ReactContainer now forwards route parameters as props to component
* `pluginlist` and `singlestat` panel subclasses needed to be adapted because
`panel_ctrl` now has the location provider as a property already
* adds +/- buttons to query rows in the Explore section
* on Run Query all query expressions are submitted
* `generateQueryKey` and `ensureQueries` are helpers to ensure each
query field has a unique key for react.
