DisplayProcessor: Interpret empty strings as NaN instead of 0 to support empty value map texts in Singlestat (#20952)

* WIP: intial commit

* Tests: Runs e2e tests

* Refactor: Adds BASE_URL support

* Refactor: Adds namespacing

* Refactor: Cleans up the Page api

* Build: Adds to build-branches-and-prs job for testing

* Build: Hardcoded image for now

* Refactor: Uses Selectors in App

* Refactor: Adds addDataSource flow

* WIP

* Refactor: Adds e2eScenario

* Refactor: Adds add and delete scenarios

* Refactor: Adds logging

* Refactor: Adds ability to for Selectors with variables

* Refactor: Using variable selectors instead

* Refactor: Adds flow until Share Panel

* Refactor: Adds clicking on rendered image link

* Refactor: Deletes log output

* Refactor: Updates snapshots

* Chore: Reverts changes

* Refactor: Removes log plugin because maybe it breaks yarn build

* Refactor: Adds rendered image download

* Refactor: Adds image comparison

* Refactor: Removes uncaught errors override

* Refactor: Changes order of images to compare

* Refactor: Updates truth image

* Build: Updates path to CI artifacts

* Refactor: Cleaning up types and config

* wip

* Refactor: Cleans up external api

* Refactor: More cleanup

* Refactor: More cleanup

* Refactor: Removes usages of Pages and Flows

* Refactor: Removes last traces of Cypress in spec

* Refactor: Adds comments

* Datasource/Loki: Loki now goes to Logs mode when importing prom queries
Closes #20831

* Fixes behavior and adds tests

* Update public/app/features/explore/state/actions.test.ts

* Defined explore query editor for cloudwatch

* Fix types

Closes #20762

Goavro doesn't compile on 32-bit systems.

This reverts commit 413be3a6.

Minor edits

* Add input segment

* Rename story

* Cleanup

* Fix lint error

* More cleanup

* Use measure text util

* Keep value in local state

* Add input segment

* Rename story

* Cleanup

* Fix lint error

* More cleanup

* Export ui component

* Use measure text util

* Update debian-ubuntu installation

Major rework of debian.md, minor updates to a configuration.md and upgrading.md.

* updated docs

Updated per Torkel's comments

* Update debian.md

Added wget to common properties install command

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Apply suggestions from code review

Co-Authored-By: Dan Cech <dcech@grafana.com>

* Update upgrading.md

* Update upgrading.md

* Update debian.md

Added ARM link

Updated "open source" word usage.

Updates the docs to work with the website repo - mainly 
relative link updates.
Adds a menu.yaml file to build the sidebar menu (no longer 
using front matter weight).

* Minor fix for meta analytics event

* Fixed dashboardSrv issue

* Added timeSinceNavigationStart

* Chore/Tech debt: Remove (most) instances of $q angular service use
Removes instances where the angular $q service is used and replaces
it with native Promises.

* Introduce Echo for collecting frontend metrics

* Update public/app/core/services/echo/Echo.ts

Co-Authored-By: Peter Holmberg <peterholmberg@users.noreply.github.com>

* Custom meta when adding event

* Rename consumer to backend

* Remove buffer from Echo

* Minor tweaks

* Update package.json

* Update public/app/app.ts

* Update public/app/app.ts

* Collect paint metrics when collecting tti. Remove echoBackendFactory

* Update yarn.lock

* Move Echo interfaces to runtime

* progress on meta and echo

* Collect meta analytics events

* Move MetaanalyticsBackend to enterprise repo

* Fixed unit tests

* Removed unused type from test

* Fixed issues with chunk loading (reverted index-template changes)

* Restored changes

* Fixed webpack prod

* initial changes - removal from state, remove anon functions, reset secrets empty

* post testing cleanup

* init promise cancellation, other cleanup

* workspaces response parser, remove version incrementing

* update datasource funcs - DRYer

* remove prop mutation

* func to modify root config opt

* fix version issue

* update snapshot

* Use data frames when procesing annotation query in graphite ds

* Remove destruct

* Stop parsing 'field'

* Remove time field from query for docs queries

* Test refactor to test all versions

* Fix tests

* add GitHub action to sync docs with website repo

* remove trigger-docs-update from circleci jobs

* update access token

* FieldDisplay: added support for value mapping of no data state.

 Committer: Marcus Andersson <marcus.andersson@grafana.com>

* FieldDisplay: fixed issue when switching between modes and display numeric was null.

* ValueMapping: introduced a private function for checking null values.

* FieldDisplay: refactoring of test setup to reduce duplication.

* Docs: added info about new 'no data' value to text mapping.

* Docs: improved according to feedback. Reverted prettier formatting changes.

* FieldDisplay: removed unused import.

* Use SelectableValue for segment value

* Update cloudwatch components to use new segment props