Add block.json file support + fields config.

generators/block/templates/block.json

@@ -0,0 +1,34 @@
+{
+	"name": "<%= blockGroupName %>/<%= blockFilename %>",
+	"version": "1.0.0",
+	"title": "<%= title %>",
+	"categories": [],
+	"icon": "shortcode",
+	"preview_image": "",
+	"field_groups": [
+		{
+			"name": "content",
+			"label": "Content",
+			"fields": {
+				"title": {
+					"type": "text",
+					"label": "Title"
+				},
+				"content": {
+					"type": "wysiwyg",
+					"label": "Content"
+				},
+				"cta": {
+					"type": "link",
+					"label": "CTA"
+				}
+			}
+		},
+		{
+			"name": "styling",
+			"label": "Styling",
+			"fields": {
+			}
+		}
+	]
+}