Merge branch '12-add-gitlab-templates' into 'main'

Add GitLab templates

Closes #12

See merge request !4

.gitlab/issue_templates/default.md

+## Summary
+
+(Summarize the issue encountered concisely)
+
+## Steps to reproduce
+
+(How one can reproduce the issue)
+
+## What is the current issue behaviour?
+
+(What actually happens)
+
+## What is the expected correct behaviour?
+
+(What you should see instead)
+
+## Relevant logs and/or screenshots
+
+(Paste any relevant logs/screenshots)
+
+## Possible fixes
+
+(Any ideas on how to fix the issue)

.gitlab/merge_request_templates/default.md

+## What does this MR do?
+
+(Summarise what this MR does)
+
+## Relevant screenshots
+
+(Add any relevant screenshots of MR's functionality)
+
+## Testing
+
+(Add detailed checkbox test steps for reviewer)
+
+## Relevant issues
+
+(List the relevant issues, i.e. `Closes #...`)