Add customizable writers, configs, chain spec in network

cic/data/config/config.ini

@@ -0,0 +1,4 @@
+[cic_core]
+meta_writer = cic.output.KVWriter
+attachment_writer = cic.output.KVWriter
+proof_writer = cic.output.KVWriter

cic/data/network_template_v0.json

@@ -1,14 +1,23 @@
 {
-	"token": {
-		"reference": null,
-		"key_account": null
+	"chain_spec": {
+		"arch": null, 
+		"fork": null,
+		"network_id": null,
+		"common_name": null,
+		"extra": {}
 	},
-	"token_index": {
-		"reference": null,
-		"key_account": null
-	},
-	"address_declarator": {
-		"reference": null,
-		"key_account": null
+	"contents": {
+		"token": {
+			"reference": null,
+			"key_account": null
+		},
+		"token_index": {
+			"reference": null,
+			"key_account": null
+		},
+		"address_declarator": {
+			"reference": null,
+			"key_account": null
+		}
 	}
 }