Complex values are supported only in config file but not on CLI

[den-is]

For now, ktempl supports complex values declaration only via config file provided via -c, --config, config.yaml in the same dir with ktempl or /etc/ktempl/config.yaml

Complex values are:

# maps
mymap:
  color: red
  active: true

# lists
mylist:
- one
- two
- 3

It should be allowed to pass complex values using --set and dot-notation like it is done in helm

Probably for that to work it will be required to review each user-passed --set argument.
Then try and parse it into map[string]interface{} and then merge into values from the config file