Annotations: Change indices and rewrites annotation find query to improve database query performance (#21915)

Drop indices and create new ones and rewrites annotation find query 
to address performance issues when querying annotation table and 
there is a large amount of rows.

Fixes #21902

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>
Co-authored-by: Kyle Brandt <kyle@kbrandt.com>

Fixes #21914

* CircleCI: Move postgres/mysql integration tests to step after linting
* CircleCI: Implement publishing of packages and Docker images for new master pipeline

Adds back missing summary quantiles which was mistakenly
removed in v6.6.0. 

Fixes #21857

* delete redundant alias

Fixes #21906

* Added developer-resources.md

Added Developer resources and updated menu.yaml file

* Updated menu.yaml

Updated menu.yaml, changed folder name, and removed redundant file building_from_source.md and containing folder

* Removed links to deleted file

* Plugins: Add default query to PromQueryEditor

* Plugins: Update PromQueryEditor snapshot

* Plugins: Use Partial for default PromQuery

* DatasourceEditor: Add UI to edit custom HTTP headers

Support for custom headers was added in #11643 but was missing in the UI.

Fixes #12779

* Review

* Layout updates

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

* Datasource: Show access (Browser/Server) select on the Prometheus datasource configuration editor

* Trigger build

Fix typo in templating JSON

One has to use "grafana/grafana" image - only using "grafana" will
result in an error message like this:
Error response from daemon: pull access denied for grafana, repository does not exist or may require 'docker login'

It's a good idea to daemonize new container. The install instructions
for Docker do this, and this instructions assume that running container
already is daemonized (otherwise you wouldn't have to stop it).

Best practise would be to create a new container, then stop old one and
start new one - this would reduce downtime. To keep instructions simple
and understandable, I didn't include that.

* Add new global built-in variables #20523
new branch from master

* #20523 Revert change on __from and __to like requested

* #20523 simplify contextSrv access

* #20523 simplify contextSrv access

* #20523 repair jest tests

* reimplement hidefromtabs

* remove console log

* going with option b instead

* less explicit

Implements initial support for resources using v0.14.0 of SDK.

Ref #21512

This is to make the custom dockerfiles compatible with our instruction
to use persitent volumes for the /var/lib/grafana dir. Without this
change the contents of that folder will be overshadowed by the persitent
volume and none of the pre-installed plugins will be available.

Image Rendering: Fix render of graph panel legend aligned to the right using Grafana image renderer plugin/service (#21854)

Don't render class body--phantomjs on body element when 
PhantomJS renderer not is in use.

Fixes #21830