- changed `start()` to return promise on main language feature task
- promise resolves to list of secondary tasks
- speeds up time to interaction of metric selector
- lazy loading of certain metric selector and log label selector items
- loading indication of metric and log label selectors
- when instantiating a datasource, the datasource service checks if the
plugin module exports Explore components, and if so, attaches them to
the datasource
- Explore component makes all major internal pluggable from a datasource
`exploreComponents` property
- Moved Prometheus query field to promehteus datasource and registered
it as an exported Explore component
- Added new Start page for Explore, also exported from the datasource
Implements rudimentary support for placeholder values inside a string
with the `PlaceholdersBuffer` class. The latter helps the newly added
sum aggregation query suggestion to automatically focus on the label
so users can easily choose from the available typeahead options.
Related: #13615
- use global range types
- add ErrorBoundary around individual Explore components
- fix table merge on empty results
- fix TimePicker date parsing on ISO dates
- fix TimePicker range string after relative move
Existing querying was grouped together before handed over to the
datasource. This slowed down result display to however long the slowest
query took.
- create one query transaction per result viewer (graph, table, etc.)
and query row
- track latencies for each transaction
- show results as soon as they are being received
- loading indicator on graph and query button to indicate that queries
are still running and that results are incomplete
- properly discard transactions when removing or changing queries
