Split APT functionality to a separate sample

Right now agdkTunnel is used to demonstrate all of the agdk APIs, but some APIs are pretty simple (such as memory advice api); others are complicate to build and to use. For example, APT set up is pretty demanding (protobuf for example), it might have negative impact on the usability of other parts of sample. For the simple APIs, it would be good to be able:

- download sample
- compile as-is
- run and trace code

Toward this end, could the APT usage be split out from the current agdktunnel sample? thank you for the consideration.

Start by locating the agdktunnel sample and tracing where its APT setup and protobuf dependency enter the build. Done means APT usage is separated while the remaining sample can be downloaded, compiled as-is, run, and traced for the simpler AGDK APIs.

Written by the indexing model from the issue text.