enhancement: reduce generated JSON size

[sielaq]

Hi

this is a simple PoC for generating smaller JSON
and also preparing client-list.tmpl to read such a JSON

#92

[sielaq]

problem:

the library you have, which is used here
https://github.com/akamai/AkamaiOPEN-edgegrid-golang/blob/master/pkg/clientlists/client_list.go#L85-L87
is missing omitempty for not relevant fields, like

	ListItemPayload struct {
		Value          string   `json:"value"`
		Tags           []string `json:"tags,omitempty"`
		Description    string   `json:"description,omitempty"`
		ExpirationDate string   `json:"expirationDate,omitempty"`
	}

so the change would need to be done together with client-list.tmpl.
my suspicious is that, we don't need to change create_clientlist.go, marshal should respect omitempty and make a smaller readable JSON.

[aka-mark]

Is there a specific issue that you are running into with large JSON configurations?
Thank you