# Functions
CreateEnv will only create.
CreateOrUpdateEnv will create or update env.
DeleteEnv will delete env locally.
GetCurrentEnvName will get current env name.
GetEnvByName will get env info by name.
GetEnvDirByName will get env dir from name.
ListEnvs will list all envs.
SetEnv will set the current env to the specified one.
UpdateEnv will update Env, if env does not exist, return error.
# Constants
ProductionACMEServer is the production ACME Server from let's encrypt.