feat: add app_json to application (#188)

* feat: add app_json to application

* fix: review comment

* fix: review comment

* fix: review comment

* textarea for initial json in applications form

* check/uncheck overide app_json will not erase app_json, update faile still have app_json

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Co-authored-by: Quan HL <quanluuhoang8@gmail.com>
Co-authored-by: Dave Horton <daveh@beachdognet.com>

src/api/types.ts

@@ -235,6 +235,7 @@ export interface Account {
 
 export interface Application {
   name: string;
+  app_json: null | string;
   call_hook: null | WebHook;
   account_sid: null | string;
   messaging_hook: null | WebHook;