[RFC]: Create Capabilities Route

[OverDsh]

Feature Description
The /capabilities route would be a versioned route that clients can use to ask the node what optional features it supports

Implementation Details
Make a shared file (capabilities.ts) in src/shared that contains an enum of every optional features (add that step to the contributing documentation) that will be used by the route to make a type-safe schema

---

• I checked that my feature request isn't a duplicate.
• I have read the CONTRIBUTING.md file.
• I certify that this contribution is my own original work, or that I have the clear legal right to submit it under the project's Apache License 2.0.