Add ability to read controller nodeport IP from file

Add ability to read controller nodeport IP from file

- Formalize use of cloverctl config file using viper
- Default name of config file is '.cloverctl.yaml'
- Look for file in home directory or relative to
cloverctl executable
- Single value in config is for 'ControllerIP: <IP Address>'
- Still try and retrieve port value of clover-controller nodeport
automatically
- Still try and retrieve IP address of clover-controller LB if
GKE environment is being used and override config file value if found
in current kube context

- Improve error messaging if controller connect fails
- Clean up the CLI help output
- Modify jmeter 'get testresult' command to avoid the use
of flags and use arguments instead

Change-Id: Id95d1b3d1079ac84996681db62da1f9b6b8a88b5
Signed-off-by: earrage <eddie.arrage@huawei.com>