this change improves the instructions for
swarm join-token and swarm init;
- only print the join-token command for workers
instead of for both managers and workers, to
prevent users from copying the wrong command.
An extra line is added to explain how to obtain
the manager token.
- print a message that a token was rotated
sucesfully if '--rotate' is used.
- add some extra white-space before / after
the join commands, to make copy/pasting
easier.
this change also does some refactoring of join-token;
- move flagname-constants together with other constants
- use variables for selected role ("worker" / "manager")
to prevent checking for them multiple times, and to
keep the "worker" / "manager" sting centralized
- add an extra blank line after "join-token" instructions
this makes it easier to copy, and cleans up the
code a tiny bit
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
