This paves the way to add a second set of paths with a separate server
URL to be able to shed requests to offerings and product entitlement
mapping to a separate server.
### Changes:
- New `HTTPRequestPath` with the same properties as `HTTPRequest.Path` +
a new `serverHostURL`
- Moved proxy logic from `SystemInfo`/`HTTPClient` to `HTTPRequestPath`
- Simplified `HTTPRequest` implementation
