platform: add deprecation path for mg::BufferUsage for the android platform. This adds a path to create a software buffer, and a path to make a buffer with native format/flags for hardware/other platform usages.
note: this is part of the effort trying to pull MirBufferUsage from client api for 1.0.
Approved by mir-ci-bot, Alan Griffiths, Cemil Azizoglu.