a fix for new nodes that are joining the anvil cluster. Instead of running only the add unit steps of each role, anvil has to also run the terraform init and install application steps. Otherwise, if a new node wants to join with a role that bootstrap node does not have, the usage of only the add unit step fails. At this point, the terraform plan of the role has not been initialized yet and the charmed application has not been installed
an overall refactor of bootstrap and join commands to make them more comprehensible
This PR includes the following: