Create pull_request_template.md (#1779)

### ❔What, Why & How

Add PR template description to streamline the PR creation and reminding
of tasks such as release notes, and tests.
<!-- Include description of the changes that will help reviewers in
their task -->
Related to issue: _none_

### ✅ Checklist 
* [x] Add tests (E2E, unit tests)
* [x] Update RELEASENOTES.md
* [x] Update documentation (e.g. for new settings or scenarios)
<!-- Include more checklist entries, if needed -->

Author: mazhelez

.github/pull_request_template.md

@@ -0,0 +1,13 @@
+### ❔What, Why & How
+
+<!-- Include description of the changes that will help reviewers in their task -->
+
+Related to issue: #
+
+### ✅ Checklist
+
+- [ ] Add tests (E2E, unit tests)
+- [ ] Update RELEASENOTES.md
+- [ ] Update documentation (e.g. for new settings or scenarios)
+
+<!-- Include more checklist entries, if needed -->