Introduce the external classes of the Topics API

- This cl may looks big but most of the changes are renaming.
- The external classes will have pattern *Request, *Response.
- Rename the internal AIDL classes to Param and Result
- Introduce the GetTopicsException and use it to propagate errors.

Test: atest AdServicesFrameworkUnitTests, atest AdServicesEndToEndTests,
atest AdServicesServiceCoreUnitTests
Bug: 223684663

Change-Id: I3f4299edb3099e09bd9326e8dd39ea39c45fb8df
18 files changed