Add action to add all issues to the project board

[oruebel]

Here a GitHub action to automatically add all issues to our project board.

Before merging this PR we need to complete the following set up steps

1. Create a GitHub App:

   • Go to your GitHub account settings.
   • Navigate to Developer settings -> GitHub Apps.
   • Click on New GitHub App.
   • Fill in the required fields and set the necessary permissions:
     • Repository permissions: Issues (Read & Write)
     • Organization permissions: Projects (Read & Write)
   • Click Create GitHub App.
   • Generate a private key and download the .pem file.

2. Store GitHub App ID and Private Key as Secrets:

   • Go to your repository on GitHub.
   • Navigate to Settings -> Secrets and variables -> Actions secrets.
   • Add a new secret for the App ID (APP_ID).
   • Add another secret for the private key (APP_PEM), pasting the content of the .pem file.

3. Install the GitHub App on Your Organization:

   • Go to the GitHub App settings page.
   • Click on Install App in the left sidebar.
   • Select your organization from the list.
   • Choose the repositories you want the app to have access to.
   • Complete the installation.

4. Merge and test the workflow

   • Merge the PR and create a test issue to make sure the workflow correctly adds the issue the board

[oruebel]

@ajtritt @rly can you help me with this. I tried to create the GitHub app according to the above instructions, but for some reason I can't see the lbl-cbg organization when trying to install the app. I checked permission, but can't seem to find the problem.