Dashboard provisioning. Replace folder property with path

* plugin_lib:
  moves datasource plugin model to grafana/grafana_plugin_model

fixed duplicate dev dependency, closes #10542

corrected build instructions, #10532

Simplified build instructions i

removed build clean from test task, #10532

Renames folder (in options) to path to make it
different from the grafana folder wherein the
dashboard will be created.

* tag filter: initial react component

* dashboard: move tag filter to filterbox

* tag filter: customize value rendering

* tag filter: get color from name

* tag filter:  custom option renderer

* tag filter: mode with tags in different container

* tag filter: refactor

* refactoring PR #10519

* tag filter: refactor of PR #10521

dashboard json cannot contain fixed id when importing from
disk. We used to override this but it didnt caught all problems
so now we block dashboards from beeing imported instead.

closes #10504

* backend_plugins: (34 commits)
  code style fixes
  Adds Table in backend datasource contract.
  Adds Tables types to protobuf
  Review tsdb protobuf contract
  supports windows compatible plugin binaries
  moves plugin proxy to plugin package
  improves name for plugin logger
  uses pluginmanagers log instead of global
  removes commented code
  makes datasource handshake more explicit
  backend plugins: improves logging
  dont spawn new subprocess while shutting down
  plugins: restart killed plugins
  query result should be a map
  test for plugin path builder
  merge backend datasources and datasources
  use int64 for timestamps
  fixes invalid valud/timestamp order
  merge backend-datasource and datasource type
  fixes broken unit test
  ...

* master: (117 commits)
  fix: share snapshot controller was missing ngInject comment, fixes #10511
  Use URLEncoding instead of StdEncoding to be sure state value will be corectly decoded (#10512)
  Optimize metrics and notifications docs
  Optimize cli and provisioning docs
  docs: Guide for IIS reverse proxy
  changelog: adds note about closing #9645
  telegram: Send notifications with an inline image
  telegram: Switch to using multipart form rather than JSON as a body
  telegram: Fix a typo in variable name
  fix: alert list pause/start toggle was not working properly
  fix template variable selector overlap by the panel (#10493)
  dashboard: Close/hide 'Add Panel' before saving a dashboard (#10482)
  fix: removed unused param
  Fix variables values passing when both repeat rows and panels is used (#10488)
  moved angular-mocks out of dependencies
  ux: minor change to alert list page
  ux: minor word change to alert list
  fix: updated snapshot test
  Add eu-west-3 in cloudwatch datasource default's region (#10477)
  fix: Make sure orig files are not added to git again #10289
  ...

Fix docs

Add support for inline image uploads to telegram notifier plugin

If image upload is enabled, but there is no public image repository,
fall back to sending an image via telegram's API.

This is a pre-requisite for uploading inline images.

Fixes #10472