Add GlobalConfig to customize Winscope behavior for testing

Add a GlobalConfig object that provides different
configs/values depending on the execution mode.

GlobalConfig currently supports "DEV" and "PROD" modes.
We'll add a "TEST" mode in the future to enable/activate
mocks in e2e tests.

Bug: b/260401392
Fix: b/262389857
Test: npm run build:all && npm run test:all
Change-Id: I3451e8a8456db2bb750c81ef27ecaf7dbabff934
3 files changed