Remove IAM access-key commands

[kobajagi]

Description

IAM access-key commands are removed from API, this PR removes the related commands from CLI.

Checklist

(For exoscale contributors)

• Changelog updated (under Unreleased block)
• Testing

Testing

$ go run . iam 
Identity and Access Management

Usage:
  exo iam [command]

Available Commands:
  api-key     API Key management
  org-policy  IAM Organization Policy management
  role        IAM Role management

Flags:
  -h, --help   help for iam

Global Flags:
  -C, --config string            Specify an alternate config file [env EXOSCALE_CONFIG]
  -O, --output-format string     Output format (table|json|text), see "exo output --help" for more information
      --output-template string   Template to use if output format is "text"
  -Q, --quiet                    Quiet mode (disable non-essential command output)
  -A, --use-account string       Account to use in config file [env EXOSCALE_ACCOUNT]

Use "exo iam [command] --help" for more information about a command.