feat: autogenerate vapid keys for push notifications (#3128)

* feat: Autogenerate push notification keys
* add vapid service class and remove pushkey model
* add spec for vapid service
* unset vapid env keys
* Unset VAPID_PRIVATE_KEY env variable

Co-authored-by: Sojan Jose <sojan@chatwoot.com>
Co-authored-by: Vishnu Narayanan <vishnu@chatwoot.com>

app/javascript/shared/mixins/specs/campaignMixin.spec.js

@@ -34,5 +34,4 @@ describe('campaignMixin', () => {
     const wrapper = shallowMount(Component);
     expect(wrapper.vm.isOnOffType).toBe(true);
   });
-
 });