Add Github actions stale and first-interaction workflow (#1054)

* Add Github actions workflow

Signed-off-by: Florian Ruschbaschan <[email protected]>

* Change secret name

Signed-off-by: Florian Ruschbaschan <[email protected]>

.github/workflows/first-interaction.yml

@@ -0,0 +1,14 @@
+name: First User Interaction
+
+on: [pull_request]
+
+jobs:
+  greeting:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/first-interaction@v1
+        with:
+          repo-token: ${{ secrets.PAT_SECRET }}
+          pr-message: |-
+            Thanks @${{ github.actor }} for taking the time to contribute to hawkBit! We really appreciate this. Make yourself comfortable while I'm looking for a committer to help you with your contribution.
+            Please make sure you read the [contribution guide](https://github.com/eclipse/hawkbit/blob/master/CONTRIBUTING.md) and signed the Eclipse Contributor Agreement (ECA).

.github/workflows/stale.yml

@@ -0,0 +1,23 @@
+name: Mark & close stale issues
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "0 0 * * *"
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v3
+        with:
+          repo-token: ${{ secrets.PAT_SECRET }}
+          days-before-stale: -1
+          days-before-close: 15
+          stale-issue-label: 'awaiting'
+          close-issue-message: |-
+            There has been no response from the original author so I closed this issue.
+            Please reach out if you have or find the answers we need so that we can investigate further.
+          only-labels: 'awaiting'
+          skip-stale-issue-message: 'true'
+          skip-stale-pr-message: 'true'