stoclient: improve config-init experience a bit

Author: joonas-fi

docs/data-interfaces/client/index.md

@@ -55,6 +55,15 @@ file: /home/joonas/varastoclient-config.json
 
 Running `$ sto config-init` without any arguments will give you instructions.
 
+You'll find `authToken` under `Web UI > Users > API keys`
+
+After you've run `config-init` successfully, run `config-print` again to check config's
+validity and what it contains.
+
+!!! tip
+	You'll have to change `tls_insecure_skip_validation` to `true`, unless you'll have
+	configured a custom SSL certificate.
+
 
 How does the cloning interface look like?
 -----------------------------------------

pkg/stoclient/config.go

@@ -93,8 +93,11 @@ func ConfigFilePath() (string, error) {
 func configInitEntrypoint() *cobra.Command {
 	return &cobra.Command{
 		Use:   "config-init [serverAddr] [authToken] [fuseMountPath]",
-		Short: "Initialize configuration, use https://localhost for dev",
-		Args:  cobra.ExactArgs(3),
+		Short: "Initialize configuration (helps writing JSON file)",
+		Long: `	serverAddr looks like https://localhost
+	authToken looks like dTPM59uxWm_uloW4...
+	fuseMountPath looks like /mnt/varasto/stofuse OR leave it as empty ("")`,
+		Args: cobra.ExactArgs(3),
 		Run: func(cmd *cobra.Command, args []string) {
 			serverAddr := args[0]
 			authToken := args[1]