elasticsearch: alerting support

[skip ci]

alert list panel: filter alerts by name, dashboard, folder, tags

- added Prometheus query date alignment

Handle all replacements if interval template variables in the client.
Fix issue with client and different versions.
Adds better tests of the client

[skip ci]

[skip ci]

changes to save modal when saving an updated dashboard

Changed time range and variables are now not saved by default, 
you'll need to actively choose if you want to save updated time 
range and or variables.

[skip ci]

Validate uid when importing dashboards

devenv: initial scripts for setting up devenv

[skip ci]

Fix CSS to hide grid controls in fullscreen/low-activity views

[skip ci]

fix singlestat threshold tooltip

Explore: Time selector, split view, design integration

* there was a comma missing to hide the handles, fixed now
* added new styles to hide header interaction in full screen panels

Fix cache busting for systemjs imports for plugins

[skip ci]

influxdb: support count distinct aggregation

this commit enable relatives path for provisioning dashboards.
this enables easier dev setups

Show create dashboard link if at least editor in one folder

Changed Prometheus interval-alignment to cover whole panel range

[skip ci]

As public/app/plugins/datasource/cloudwatch/partials/config.html and this file differ between the AWS regions available, I've updated the latest so they share the same data.
In that way, the regions() method in dashboards returns the same list as the frontend does.

graphite: avoid distributed tracing headers in direct/browser mode