Adding issue templates to Github

[spjuhel]

Changes proposed in this PR:

• Adding issue templates to the GitHub platform

PR Author Checklist

• Read the Contribution Guide
• Correct target branch selected (if unsure, select develop)
• Descriptive pull request title added
• Source branch up-to-date with target branch
• Documentation updated
• Tests updated
• Tests passing
• No new linter issues
• Changelog updated

PR Reviewer Checklist

• Read the Contribution Guide
• CLIMADA Reviewer Checklist passed
• Tests passing
• No new linter issues

[spjuhel]

The doc on this: https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository

It is also possible to create issue forms: https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/configuring-issue-templates-for-your-repository#creating-issue-forms

[peanutfun]

Very nice addition, I highly welcome these templates! I have a few suggestions for improvement, see my comments.

[chahank]

Fully agree! Thanks @spjuhel. I just proposed one small addition to help unexperienced users to find the information on their operating system and their Python version. Otherwise, I would propose to merge.