feat: Add support for Drawer widget

[divyanshub024]

Description

Add support for the Drawer widget

[vinothvino42]

@divyanshub024 I’ll begin working on this issue and update the status soon

[vinothvino42]

@divyanshub024 Can you suggest the JSON structure for opening and closing a drawer? Need actions for openDrawer, openEndDrawer, closeDrawer and closeEndDrawer.

Mirai JSON

Action: openDrawer, closeDrawer, openEndDrawer, closeEndDrawer

"onPressed": {
   "actionType": "openDrawer",
 }

Can you suggest some approach? As of now I've done by adding a global key of type scaffold state in the mirai scaffold final miraiScaffoldKey = GlobalKey<ScaffoldState>(); and assigned it to scaffold widget.

In MiraiDrawerActionParser's onCall method, I'll use this global key for opening / closing a drawer.

Here's the WIP PR - #184