Docs: Add guidelines for PR/commit messages (#17190)

CONTRIBUTING.md

@@ -31,6 +31,8 @@ To setup a local development environment we recommend reading [Building Grafana
 
 
 * Add tests relevant to the fixed bug or new feature.
 * Add tests relevant to the fixed bug or new feature.
 
 
+* Follow [PR and commit messages guidelines](#PR-and-commit-messages-guidelines)
+
 ### Pull requests with new features
 ### Pull requests with new features
 Commits should be as small as possible, while ensuring that each commit is correct independently (i.e., each commit should compile and pass tests).
 Commits should be as small as possible, while ensuring that each commit is correct independently (i.e., each commit should compile and pass tests).
 
 
@@ -38,12 +40,12 @@ Make sure to include `Closes #<issue number>` or `Fixes #<issue number>` in the
 
 
 ### Pull requests with bug fixes
 ### Pull requests with bug fixes
 Please make all changes in one commit if possible. Include `Closes #<issue number>` in bottom of the commit message.
 Please make all changes in one commit if possible. Include `Closes #<issue number>` in bottom of the commit message.
-A commit message for a bug fix should look something like this.
+A commit message for a bug fix should look something like this:
 
 
 ```
 ```
-avoid infinite loop in the dashboard provisioner
+Dashboard: Avoid infinite loop in the dashboard provisioner
 
 
-if one dashboard with an uid is refered to by two
+If one dashboard with an uid is refered to by two
 provsioners each provisioner overwrite each other.
 provsioners each provisioner overwrite each other.
 filling up dashboard_versions quite fast if using
 filling up dashboard_versions quite fast if using
 default settings.
 default settings.
@@ -51,6 +53,8 @@ default settings.
 Closes #12864
 Closes #12864
 ```
 ```
 
 
+For more details about PR naming and commit messages please see [PR and commit messages guidelines](#PR-and-commit-messages-guidelines)
+
 If the pull request needs changes before its merged the new commits should be rebased into one commit before its merged.
 If the pull request needs changes before its merged the new commits should be rebased into one commit before its merged.
 
 
 ## Backend dependency management
 ## Backend dependency management
@@ -80,3 +84,22 @@ GO111MODULE=on go mod vendor
 ```
 ```
 
 
 You have to commit the changes to `go.mod`, `go.sum` and the `vendor/` directory before submitting the pull request.
 You have to commit the changes to `go.mod`, `go.sum` and the `vendor/` directory before submitting the pull request.
+
+## PR and commit messages guidelines
+PR title and squash commit messages should follow guidelines below:
+
+```
+Area of changes: Message
+
+Detailed description
+```
+
+The `Area of changes` is related either to functional domain (i.e. Build, Release) or feature domain (i.e. Explore, Plugins, BarGaugePanel).
+
+
+`Message` should be concise, written in present tense and start with capitalised verb. Detailed description should be provided as commit message body, by entering a blank line between commit title and the description.
+
+### Examples of good PR titles/commit messages:
+- `Explore: Adds Live option for supported datasources`
+- `GraphPanel: Don't sort series when legend table & sort column is not visible`
+- `Build: Support publishing MSI to grafana.com`