Fix some oo-admin-ctl-routing-tool issues

##### `oo-admin-ctl-routing`: Print usage with no args
    
Print usage information and exit with exit code 0 if no arguments are provided or if `-h` or `--help` is provided.
    
If an unrecognized argument is provided, print out the offending argument and advise to run `oo-admin-ctl-routing` with the `--help` argument.
    
This commit fixes part 1 of bug 1169424.


##### `oo-admin-ctl-routing` usage info: Add missing `|`
    
Add a missing `|` delimiter between `delete-monitor` and `list-pool-members` in the usage information.
    
This commit fixes part 2 of bug 1169424.


##### `oo-admin-ctl-routing`: Fix `list-monitors`
    
Make `oo-admin-ctl-routing` properly handle the case where the routing daemon's backend returns nil when the list of monitors is requested.
    
This commit fixes part 3 of bug 1169424.


##### `oo-admin-ctl-routing`: Add `list-pool-aliases` usage
    
Add `list-pool-aliases` to the usage information for `oo-admin-ctl-routing`.
    
This commit addresses part 4 of bug 1169424.


##### `oo-admin-ctl-routing`: Add `list-aliases`
    
Add the `list-aliases` subcommand to `oo-admin-ctl-routing` to list all aliases of all pools.
    
This commit addresses part 4 of bug 1169424.


##### `oo-admin-ctl-routing`: Better usage output
    
Reformat the usage output for `oo-admin-ctl-user` to make it easier to read and more complete.