Clarify key types, when they are used, what permissions they have, and implement consistent usage

[leggetter]

1. CI Key
2. CLI Key
3. API Keys

See #102 (comment)

Related work items:

• Remove --api-key flag
• Change hookdeck ci to take the project api key as param so hookdeck ci some-key (we can keep --api-key on this command just for backward compatibility, not document it and print a warning)
• Change hookdeck login to accept an optional cli key as param so hookdeck login some-key
• Add a warning when using --cli-key thats it’s deprecated and login with hookdeck login some-key and remove it from the documentation
• Change config terminology from api_key to cli_key and workspace_ to project_
• Fix the issue with hookdeck login --cli-key abcxyz if already logged in. It should replace your current credentials for the current profile

But let's begin by documenting the key types.

[alexbouchardd]

Bonus to this we should support creating CLI keys from the dashboard 👀