fix: move ISSUE_TEMPLATE into .github/ subdirectory for org-level defaults to work

[jpmewenemesse]

Currently templates (bug_report.yml, feature_request.yml, config.yml) are placed at the root of this repository.
According to the Github community health documentation, it must be in a folder called .github/ISSUE_TEMPLATE

The Fix

Move ISSUE_TEMPLATE to .github/ subdirectory in order for them to take effect at org level