Add GitHub issue and bug report templates

[RBhupi]

Bug report pre-fills bug label. Feature request pre-fills enhancement.

Bug report template should capture

1. Adapt version
2. OS and Python version
3. Steps to reproduce
4. Expected vs actual behaviour
5. • The command and Config file
   • Full traceback / error log

Whether the issue is reproducible with the example data

Feature request template should capture

• Problem
• solution
• Whether this is science-driven or infrastructure?
• How would you use this feature?

[RBhupi]

PR #15 Closes this issue.