[v9.4.x] docs: upgrade guide refactor organizes releases into their own pages; moves upgrade guide to the root (#62987)

docs: upgrade guide refactor organizes releases into their own pages; moves upgrade guide to the root (#62402)

* organizes releases into their own pages; moves upgrade guide to the root

* adds and removes aliases

* Update docs/sources/upgrade-guide/upgrade-v8.0/index.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/upgrade-guide/upgrade-v8.0/index.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/upgrade-guide/upgrade-v8.0/index.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/upgrade-guide/upgrade-v9.3/index.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/shared/upgrade/upgrade-common-tasks.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/shared/upgrade/upgrade-common-tasks.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* Update docs/sources/shared/upgrade/upgrade-common-tasks.md

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>

* corrects relrefs

---------

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>
(cherry picked from commit ee2e294b4e)

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

docs/sources/release-notes/release-notes-7-3-0.md

@@ -56,7 +56,7 @@ title: Release notes for Grafana 7.3.0
 
 ### Breaking changes
 
-- **CloudWatch**: The AWS CloudWatch data source's authentication scheme has changed. See the [upgrade notes]{{< relref "../setup-grafana/upgrade-grafana/#upgrading-to-v73" >}}) for details and how this may affect you.
+- **CloudWatch**: The AWS CloudWatch data source's authentication scheme has changed.
 
 ### Features and enhancements