this is a fix-up PR that cleans up Explore Logging after the recent
restructuring.
- log results need to be merged since query transactions have been
introduced
- logging DS has its own language provider, query field, and start page
(some of them based on prometheus components)
- added loader animation to log viewer
- removed logging logic from prometheus components
- 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
The grafana_stats.json used the following prometheus query: "increase(grafana_alerting_result_total[1m])" But a metric called "grafana_alerting_result_total" is currently not there anymore. So i changed the query to "increase(grafana_alerting_active_alerts[1m])" and updated the title as well (Before: "Grafana alert results", Now: "Grafana active alerts").
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
No label suggestions were being returned for multi-line aggregation
contexts because the parsed selector string does not see the full
context before a `by` or `without` clause.
This solution stitches together all text nodes that comprise the query
editor to ensure the selector has sufficient context to generate
suggestions.
Also, an additional workaround has been included to ensure range vector
syntax does not disrupt label suggestions in aggregation contexts.
Related: #12890
* stackdriver: add resource type to filter and group bys
* stackdriver: remove not used param
* stackdriver: refactor filter and group by code
* stackdriver: remove resource type if its already in filter list
* stackdriver: remove debug logging
* stackdriver: remove more debug logging
* stackdriver: append resource type to legend name if there are more than one type present in the response
* stackdriver: only make new request if filter has real value
* stackdriver: format legend support for resource type
* stackdriver: add resource type to documentation
* stackdriver: not returning promise from query function
* stackdriver: fix refactoring bug
* stackdriver: remove not used import
