Add alternative key name for the commit status secret

[stefanprodan]

Currently we expect for the GitHub/GitLab/etc PAT to be set under the token key in the Kubernetes Secret referenced in the Provider https://fluxcd.io/flux/components/notification/providers/#github

If token is not found in the secret, but there is a password field, we should be using it instead. The reason being that, when using a PAT for flux bootstrap --token-auth, the PAT is set in the password field. So instead of creating a new secret with the same token for the Provider, users should be able to reuse the secret created by bootstrap.

[sarataha]

Hello Stefan, I would like to work on this issue 🙂