Grafana v7.0 changelog update (#24737)

* Grafana v7.0 changelog update

* enterprise changelog

* docs: white-labeling login title and subtitle

* Add backend plugins breaking change regarding plugin signing

* Update CHANGELOG.md

Co-authored-by: Kyle Brandt <kyle@grafana.com>

* Update docs/sources/installation/upgrading.md

Co-authored-by: Kyle Brandt <kyle@grafana.com>

* Update docs/sources/installation/upgrading.md

Co-authored-by: Leonard Gram <leo@xlson.com>
Co-authored-by: Kyle Brandt <kyle@grafana.com>

docs/sources/installation/upgrading.md

@@ -243,8 +243,12 @@ change the `[security]` setting `cookie_secure` to `true` and use HTTPS when `co
 
 ### PhantomJS removed
 
-PhantomJS was deprecated in [Grafana v6.4](https://grafana.com/docs/grafana/latest/guides/whats-new-in-v6-4/#phantomjs-deprecation) and starting from Grafana v7.0.0, all PhantomJS support has been removed. This means that Grafana no longer ships with a built-in image renderer, and we adwise you to install the [Grafana Image Renderer plugin](https://grafana.com/grafana/plugins/grafana-image-renderer).
+PhantomJS was deprecated in [Grafana v6.4]({{< relref "../guides/whats-new-in-v6-4.md#phantomjs-deprecation" >}}) and starting from Grafana v7.0.0, all PhantomJS support has been removed. This means that Grafana no longer ships with a built-in image renderer, and we adwise you to install the [Grafana Image Renderer plugin](https://grafana.com/grafana/plugins/grafana-image-renderer).
 
 ### Dashboard minimum refresh interval enforced
 
 A global minimum dashboard refresh interval is now enforced and defaults to 5 seconds. Read more [here]({{< relref "configuration/#min-refresh-interval" >}}) about this setting.
+
+### Backend plugins
+
+Grafana now requires backend plugins to be signed. If a backend plugin is not signed Grafana will not load/start it. This is an additional security measure to make sure backend plugin binaries and files haven't been tampered with.  All Grafana Labs authored backend plugins, including Enterprise plugins, are now signed. It's possible to allow unsigned plugins using a configuration setting, but is something we strongly advise against doing. Read more [here]({{< relref "configuration/#allow-loading-unsigned-plugins" >}}) about this setting.

packages/grafana-toolkit/CHANGELOG.md

+# 7.0.0 (2020-05-18)
+
+### Bug Fixes
+
+* **@grafana/toolkit**: Use process.cwd() instead of PWD to get directory. [#24677](https://github.com/grafana/grafana/pull/24677), [@zoltanbedi](https://github.com/zoltanbedi)
+
 # 7.0.0-beta.1 (2020-04-28)
 
 ### Features / Enhancements

packages/grafana-ui/CHANGELOG.md

+# 7.0.0 (2020-05-18)
+
+### Bug Fixes
+
+* **Explore**: Fixes loading more logs in logs context view. [#24135](https://github.com/grafana/grafana/pull/24135), [@Estrax](https://github.com/Estrax)
+
 # 7.0.0-beta3 (2020-05-08)
 
 ### Features / Enhancements