Set rabbitmq user for enabling plugins

[iustinam90]

There is currently a permission issue when enabling plugins. As in https://github.com/saltstack/salt/blob/6086ee452725c83044064a881ddabbc7895909a4/salt/modules/rabbitmq.py#L1004, the command to enable plugins is ran as 'runas' user, and if not set, with the same user as salt. For rabbitmq there is normally a separate rabbitmq user, and we can overwrite the default behaviour by setting 'runas' to that user.

[fpytloun]

Thank you :)

[iustinam90]

sorry, I think the best way to handle this is by adding read permission to group/others https://github.com/rabbitmq/rabbitmq-server/issues/1129