Stale action re-configure (still just debug mode) (#21783)

* Remove old stale bot yaml file

* Remove slack svg file (unused)

* Stale action: Only apply stale label, and no other actions

Respecting the opinion on
https://github.com/PX4/PX4-Autopilot/commit/fa9ac6ecf651232f3105ca124a2d2c54ab8620d0,
it seems reasonable to disable commenting feature, and just keep the
action only applying the `stale` label. This will reduce the noise /
email spams / ping pong fight with the stale bot (Action)

.github/workflows/stale.yml

@@ -1,4 +1,4 @@
-name: 'Close stale issues and PRs'
+name: 'Handle stale issues and PRs'
 on:
   schedule:
     - cron: '30 1 * * *'
@@ -9,12 +9,11 @@ jobs:
     steps:
       - uses: actions/stale@v4.1.1
         with:
-          stale-issue-message: 'This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.'
-          stale-pr-message: 'This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.'
-          close-issue-message: 'This issue was closed because it has been stalled for 5 days with no activity.'
-          close-pr-message: 'This PR was closed because it has been stalled for 10 days with no activity.'
           days-before-issue-stale: 30
-          days-before-pr-stale: 45
-          days-before-issue-close: 5
-          days-before-pr-close: 10
+          stale-issue-label: 'stale'
+
+          days-before-pr-stale: 30
+          stale-pr-label: 'stale'
+
+          remove-stale-when-updated: true
           debug-only: true