DOC: Add First Interaction GitHub Action

Closes #1533

.github/workflows/first-interaction.yml

@@ -0,0 +1,19 @@
+name: First interaction
+
+on:
+  - pull_request_target
+  - issues
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      issues: write
+
+    steps:
+    - uses: actions/first-interaction@v1
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"
+        issue-message: '# Thank you for contributing an issue\n**Welcome to the ITK community!**\nWe are glad you are here and appreciate your contribution. Please keep in mind our [community participation guidelines](https://github.com/InsightSoftwareConsortium/ITK/blob/master/CODE_OF_CONDUCT.md).\nAlso, please check [existing open issues](https://github.com/InsightSoftwareConsortium/ITK/issues) and consider discussion on the [ITK Discourse](https://discourse.itk.org).'
+        pr-message: '# Thank you for contributing a pull request\n**Welcome to the ITK community!**\nWe are glad you are here and appreciate your contribution. Please keep in mind our [community participation guidelines](https://github.com/InsightSoftwareConsortium/ITK/blob/master/CODE_OF_CONDUCT.md).\nMore support and guidance on the contribution process and be found in our [contributing guide](https://github.com/InsightSoftwareConsortium/ITK/blob/master/CONTRIBUTING.md).'