Rebranding: it is Audio Plugins For Android now

[atsushieno]

I have renamed the repository and the entire project name:

• Android Audio Plugin Framework => Audio Plugins For Android
• android-audio-plugin-framework => aap-core

It is mostly to avoid possible future problem on trademarks (avoiding Android as the first term is a common trick e.g. Windows Subsystem for Android).

We'd still use AAP as the traditional acronym. AP4A/APfA might fork too, I don't care much.

This repository is renamed to make better sense. I'm actually not sure if framework is an appropriate naming. It's more about a plugin format. But apparently we also need implementation and that determines framework. aap-core is not confusing anyways.

Library names are kept as androidaudioplugin*.aar and libandroidaudioplugin*.so. It's not about implementation names.