Improve examples for various scenarios in blade -h #1131

Usage:
  blade create cpu fullload

Aliases:
  fullload, fl, load

Examples:

# Create a CPU full load experiment
blade create cpu load

#Specifies two random core's full load
blade create cpu load --cpu-percent 60 --cpu-count 2

# Specifies that the core is full load with index 0, 3, and that the core's index starts at 0
blade create cpu load --cpu-list 0,3

# Specify the core full load of indexes 1-3
blade create cpu load --cpu-list 1-3

# Specified percentage load
blade create cpu load --cpu-percent 60

Flags:
      --blade-release string     Blade release package，use this flag when the channel is ssh
      --cgroup-root string       cgroup root path, default value /sys/fs/cgroup
      --channel string           Select the channel for execution, and you can now select SSH
      --climb-time string        durations(s) to climb
      --cpu-count string         Cpu count
      --cpu-index string         cpu index, user unavailable!
      --cpu-list string          CPUs in which to allow burning (0-3 or 1,3)
      --cpu-percent string       percent of burn CPU (0-100)
  -h, --help                     help for fullload
      --install-path string      install path default /opt/chaosblade，use this flag when the channel is ssh
      --override-blade-release   Override blade release，use this flag when the channel is ssh
      --ssh-host string          Use this flag when the channel is ssh
...