Add Stale-bot

This file configures the following stale-bot:
https://github.com/apps/stale

It is set to mark issues as "Stale" after 365 days
It is also set to auto-close the issue 90 days after.

Please be aware that this issue also requires-
The listed stale-bot being added to the repo.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Closes #10778

.github/stale.yml

@@ -0,0 +1,17 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 365
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 90
+# Limit to only `issues` or `pulls`
+only: issues
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - "Type: Feature"
+  - "Type: Understood"
+# Label to use when marking an issue as stale
+staleLabel: "Status: Stale"
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  This issue has been automatically marked as "stale" because it has not had
+  any activity for a while. It will be closed in 90 days if no further activity occurs. 
+  Thank you for your contributions.