Move hiddenapi singleton rules to Soong

Move the rules that build hiddenapi-stubs-flags.txt,
hiddenapi-flags.csv and hiddenapi-greylist.csv into Soong.

Bug: 123645297
Test: m checkbuild
Test: m UNSAFE_DISABLE_HIDDEN_API_FLAGS=true
Change-Id: I90bf58710f6153ee8565994f799d3ec5699bc7fa