extract accounts and add integration test

- add end-to-end test AccountsEndpoint
- extract get accounts from account.http to accounts.http
- extract get accounts from AccountController to AccountsController
- move spring boot test file to integration test
- add schema.sql
- add dependencies for integration test

http/accounts.http

@@ -0,0 +1,8 @@
+### Get accounts
+GET {{hostname}}/accounts
+
+### Get accounts by page
+GET {{hostname}}/accounts/page-1
+
+### Get accounts by page and size
+GET {{hostname}}/accounts/page-1/show-1