Document a convention for bidirectional linking of issues (e.g. issue template, edit issue message with Jira issue link in formatted section)

It would be great if we could add support for the [Jira issue sync](https://github.com/canonical/opentelemetry-collector-k8s-operator/blob/main/.github/.jira_sync_config.yaml) per interface so that GH issues being created in charmlibs automatically land in the respective team Jira boards. Currently the user creates an issue in the charmlibs repo and then needs to manually create a Jira issue on their board to track it for roadmap purposes.

I understand this may be out of scope, but would help with company-internal ops.