add template for issues and merge request

.gitlab/issue_templates/bug.md

+## Description
+
+### Observed
+
+*Description of bug*
+
+### Expected
+
+*What behaviour you would expect*
+
+## Tasks
+
+* [ ] First step
+* [ ] Second step
\ No newline at end of file

.gitlab/issue_templates/feature.md

+## Description
+
+*Description of the new feature*
+
+## Tasks
+
+* [ ] First step
+* [ ] Second step
\ No newline at end of file

.gitlab/issue_templates/test_template.md

-# First template
-
-This is an attempt to add a template to GitLab

.gitlab/merge_request_templates/bug.md

+## Definition of Done
+
+* [ ] Test has been added to reproduce and fix the bug (*only apply for Python at the moment*)
+* [ ] Merge request has been revised and validated
+
+## Related issue(s)
+
+Closes *Issue number (e.g. #35)*

.gitlab/merge_request_templates/feature.md

+## Description
+
+*Description of the new feature (if different from the one described in the corresponding issue)*
+
+## Definition of Done
+
+* [ ] New code added is tested (*only apply for Python at the moment*)
+* [ ] Merge request has been revised and validated
+
+## Related issue(s)
+
+Closes *Issue number (e.g. #35)*