Fix and generate vndk snapshot entirely in Soong

- VNDK snapshot now respects stem and suffix.
- ld.config.txt is removed from snapshot as linkerconfig has become default.
- Soong builds entire snapshot, and make just calls dist-for-goals.

Bug: 142589718
Test: build and install snapshot
Test: development/vndk/snapshot/update.py with past version of snapshot
Change-Id: Ib99f1006d3553b1871b86ab168b1706fe47e1afb