Add build condition and instruction to add/remove submodules with STS SDK.

Bug: 255827931
Test: m sts-sdk and extract and build and run
Test: remove test-app and build and run; remove native-poc and build and run
Test: add new submodule app and build and run
Change-Id: Ia553b067e31406cbc36ac71890855d59fdd0f2b1
3 files changed
tree: 26749067cae94a6688b061a81234183957fce89a
  1. build/
  2. docs/
  3. emu_test/
  4. libraries/
  5. scripts/
  6. tests/
  7. utils/
  8. PREUPLOAD.cfg