Remove Make side (system/test-)api-stubs droiddoc targets

Remove old droiddoc targets for api-stubs, system-api-stubs, and test-api-stubs.

And also set api_tag_name, api_filename, private_api_filename, and etc.
properties in Android.bp for new droiddoc.
Test: manually compare if dependencies change after Soong based droiddoc runs.
Bug: b/70351683

Change-Id: I8d944c83de120ec8148276adc1c9872113d9d29b
Merged-In: I8d944c83de120ec8148276adc1c9872113d9d29b