Remove RefBase from plugin-side DataSource

Extractor plugins now use DataSourceBase, which is not refcounted.
Framework-side DataSource derives from DataSourceBase and RefBase.
Also remove MediaExtractor::release, because it is not needed
anymore due to the way the extractor/track/datasource lifecycle
is managed now.
Also add source and target pid to CallbackDataSource name, to
make the extractor dumpsys more useful.

Bug: 67908556
Test: build, boot, CTS, skia test app for heif
Change-Id: I6b9cbe903f76b0cf27ba87f4a456f424803efd08