consider removing the 'renewable' column from list output

[joemiller]

Tokens issued by the vault auth/okta backend have the 'renew=true' attribute set but when they're renewed with vault renew the ttl does not actually increase. I believe this is becaues the okta backend doesn't currently allow for creating period tokens that could be renewed and extended before the end of the period's ttl.

Consider removing the renewable column from the output because it's confusing.

Perhaps still available as a -flag for the case where you are storing a period token.