Replaced ubuntu:latest with ubuntu:18.04; specific image version to make grafana build images consistent (#18224)

Follow-up for 4b16cd6c

* Fix redis connstr parsing

* Don’t log the password

Fixes #17947

* Build: introduce shellcheck

Fixes #16198

* Update defaults.ini and sample.ini with the SAML assertion mapping
fields

* Document Grafana's ability to map ACS attributes while a Grafana user is created

fixes #18184

fix duplicate alert states when the alert fails to save to the database.
fixes #18176

Closes #17588

Running the command as given in the current doc throws the error:

```
sudo wget -q -O - https://packages.grafana.com/gpg.key | apt-key add -
ERROR: This command can only be used by root.
```

The proposed change fixes this issue.

* Ignore `node_modules` in watch mode

* Simplify development setup

* Reapply MetricNamespace support

* Fixing tests

* refactor: move metricnamespace param to backend

* refactor: remove unused function

* azuremonitor: migration for new metric namespace field

* azuremonitor: add template query for metric namespace with a sub

* docs: template queries for azure monitor

Adds new lines for the metricnamespace template function and fixes
some messed up lines

* tables display

* add missing file

* adding toolbar option

* adding toolbar option

* add items to index

* use root import path

* merge master

* show tables info

* add importDashboards code

* remove table changes

* remove table changes

* use deprecation warning

- the error was set, but has not been shown
- this change will force a digest before the query promises return with
their error handling

- navigating right away triggered the unsaved warning on slower machines
- this change makes sure we see a success message first

* @grafana/toolkit: make ts-loader ignore files that are not bundled

* @grafana/toolkit: improve the circleci task (#18133)

This PR makes some minor improvements to the circle task

Adds build info to plugin.json
adds dependencies to deployed artifacts
Makes sure prettier has content before writing (avoid writing empty files)
renames 'bundle' to 'package' and saves stuff in a 'packages' file

* @grafana/toolkit: enable plugin themes to work with common stylesheet (#18160)

This makes it possible to use themes styleshheet files and stylesheet imports at the same time. The problem occurred when trying to migrate polystat panel to toolkit: grafana/grafana-polystat-panel#62

Prompted by the @slim-bean talk (thanks!). With that definition
`GO_FILES` var can be dynamically changed, that will be very helpful
in grafana enterprise repo

* noImplicitAny playlist approx 200

* Add AngularPanelMenuItem interface

* Roughly 100 noImplicitAny

Adds pulse waveform. Is predictable in the sense that the start of the waveform is aligned to epoch time (instead of the start of the query time). This makes a useful signal for manual testing of alerting in the devenv.
 

* chore: mirror the Dockerhub readme

Seems like the dockerhub readme is out of sync with this one. Let's update this one to make them identical.

* chore: add changes part of 6.3.0-beta1 to the docker image README

* chore: add the date to the 6.3.0-beta1 changes in the CHANGELOG

* docs: Link to SAML docs and document configuration options

- Document configuration options `defaults.ini` and `sample.ini`
- Add the SAML documentation
- Link to the SAML documentation from "what's new in 6.3"

The script tries to delete previously existing alerts
but it used to fail if there were too many of them.

* Enable running tests in watch mode and by path or name regex

* Toolkit readme update

* Show webpack stats on successful compilation

* unzip the plugin, not the docs

* Metrics: remove unused metrics

Metric `M_Grafana_Version` is not used anywhere, nor the mentioned
`M_Grafana_Build_Version`. Seems to be an artefact?

* Metrics: make the naming consistent

* Metrics: add comments to exported vars

* Metrics: use proper naming

Fixes #18110