Update Login Script, introducing multiple breaking changes
- Rename the clusters to the form wwukube-<environment>-<location>. This includes adding prod as the environment to the production cluster.
- Use a single user "wwukube" for all clusters and remove the user from the contexts.
- Introduce new environment variable WWUKUBE_LOGIN_ENABLE_DEV. If set to "yes", this also creates kubectl configurations for the dev clusters.
- Update Certificate for wwukube-staging-ms2.