Adding a boolean field that determines whether users will be allowed to
set the ID of the signed SSH key or whether it will always be the token
display name. Preventing users from changing the ID and always using
the token name is useful for auditing who actually used a key to access
a remote host since sshd logs key IDs.
* Use constants for storage paths
* Upgrade path for public key storage
* Fix calculateValidPrincipals, upgrade ca_private_key, and other changes
* Remove a print statement
* Added tests for upgrade case
* Make exporting consistent in creation bundle
* unexporting and constants
* Move keys into a struct instead of plain string
* minor changes
* docs: input format for default_critical_options and default_extensions
* s/sshca/ssh
* Added default_critical_options and default_extensions to the read endpoint of role
* Change default time return value to 0
Jeff Mitchell