[Pod] Rename interface & impl for TableLogBuffer, move interface to pod

Previously, the interface for TableLogBuffer was named
TableLogBufferBase, and the impl was named TableLogBuffer. To match our
new conventions, this CL renames the interface to TableLogBuffer and the
impl to TableLogBufferImpl.

Also, TableLogBufferBase was in the `plugins` directory so that classes
outside of SystemUI-core could access it. With pods, we can now move the
interface into a pod. It'll still be accessible by classes outside of
SystemUI-core, but now it has a dedicated `api` soong target.

Bug: 307607958
Flag: EXEMPT refactor
Test: m SystemUI-core
Test: m SystemUISharedLib
Change-Id: I224f7e4d91e2d51482db0e708ed0a805da2ba553