feat: Adds initial pull request template

Author: darigovresearch

PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,4 @@
+- [ ] I confirm that all the content in this pull request is original work and I am the original author
+- [ ] I have nothing that prevents me from submitting this work (like a clause in a work contract)
+- [ ] I understand that the work I am submitting will be released under the terms of the licence of this repository
+  - [ ] I have double-checked all of the above and checked the tick-boxes