🎩 What? Why?

This PR introduces 2 features:

1. Allows a user acting as a Polling Officer to access the Polling Officer Zone from their account page;
2. Notifies a user when they are assigned as president/manager of a Polling Station with the instructions on how to access the Polling Officer Zone.

1. Polling Officer Zone

The Polling Officer Zone is based on the Trustee Zone implemented here: #6615

Notice that, for the moment, a Polling Officer can only see the Polling Stations they are assigned to, while the actions they con perform on the PS are not yet implemented (blank page).
The UI is rough and will be improved in upcoming tasks (and well the design will be available).

2. Polling Officer Notification

In order to only send notifications to Officers when they are assigned to a Polling Station, and not when other Polling Officers are added/removed, we now assign/unassign only those officers that need it (instead of unassign all old + assign all new as done before)

📌 Related Issues

• Fixes Access to the Polling Officer Zone #7123

📋 Checklist

🚨 Please review the guidelines for contributing to this repository.

• ❓ CONSIDER adding a unit test if your PR resolves an issue.
• ✔️ DO check open PR's to avoid duplicates.
• ✔️ DO keep pull requests small so they can be easily reviewed.
• ✔️ DO build locally before pushing.
• ✔️ DO make sure tests pass.
• ✔️ DO make sure any new changes are documented in docs/.
• ✔️ DO add and modify seeds if necessary.
• ✔️ DO add CHANGELOG upgrade notes if required.
• ✔️ DO add to GraphQL API if there are new public fields.
• ✔️ DO add link to MetaDecidim if it's a new feature.
• ❌AVOID breaking the continuous integration build.
• ❌AVOID making significant changes to the overall architecture.

📷 Screenshots

Please add screenshots of the changes you're proposing
POLLING OFFICER ZONE

NOTIFICATION

EMAIL

♥️ Thank you!