Support creating service tokens with a name

[joshmgross]

This enables creating a service token with an optional --name parameter and adds the name to the fields we show when listing service tokens.

pscale service-token create --name my_token
  ID             NAME       TOKEN                                                    CREATED AT  
 -------------- ---------- -------------------------------------------------------- ------------ 
  hnmkbklsndgi   my_token   pscale_tkn_REDACTED                                      now         


pscale service-token list
  ID (12)        NAME                     LAST USED AT   CREATED AT      
 -------------- ------------------------ -------------- ---------------- 
  hnmkbklsndgi   my_token                                19 minutes ago