Add 'aim to improve dev experience' to campaigns working agreements

Created by: mrnugget

This is also an outcome of yesterday's retrospective in which we said (okay: I said a lot) that we should try to fight back against "this has already been bad"-inertia and try to actively improve our developer experience.

Now, I didn't know how to formulate this here, which is why it might sound a bit blurry. Suggestions welcome.

Alternative proposal:

We try to fight back against "this has already been bad"-inertia and work to improve our developer experience