## Description
Since Usage & Billing is EE only, there are a few components which needs
to be code splitted. So code splitted those files and also added feature
flag for Usage & Billing.
TL;DR Code split usage and billing files
Fixes [#146](https://github.com/appsmithorg/cloud-services/issues/146)
## Type of change
> Please delete options that are not relevant.
- Code splitting
## How Has This Been Tested?
- Manual
## Checklist:
### Dev activity
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag
### QA activity:
- [ ] Test plan has been approved by relevant developers
- [ ] Test plan has been peer reviewed by QA
- [ ] Cypress test cases have been added and approved by either SDET or
manual QA
- [ ] Organized project review call with relevant stakeholders after
Round 1/2 of QA
- [ ] Added Test Plan Approved label after reveiwing all Cypress test
