OCRVS-8300 Workflow added which will close PR after 30 days of inactivity

[alsmk]

This workflow will add a label Stale to a PR (if the PR remains inactive for 20 days)
After 10 days of labeling a PR to stale it will close the PR.
and send some messages to the author.

The main purpose of the workflow is Closing a PR which is inactive for 30 days

[github-actions]

Oops! Looks like you forgot to update the changelog. When updating CHANGELOG.md, please consider the following:

• Changelog is read by country implementors who might not always be familiar with all technical details of OpenCRVS. Keep language high-level, user friendly and avoid technical references to internals.
• Answer "What's new?", "Why was the change made?" and "Why should I care?" for each change.
• If it's a breaking change, include a migration guide answering "What do I need to do to upgrade?".