Thought: remove --token global argument

[evert]

Hey I thought it might be nice to drop the --token argument, given that a custom token can also be provided on the command-line like this:

EVENTLY_TOKEN=foo evently register:list-entities

instead of

evently register:list-entities --token foo

My only reason is that it adds some clutter to every command file, and help output.

[mattbishop]

Authentication is going to change in the future to be more like Heroku works, where one signs in with an account and the token is stored. Selfishly, I like --token because in developing Evently, I can switch to different environments without changing the env var.

[evert]

Sounds good!