Update behavior of some DownloadManager APIs.

-- Update behavior of DownloadManager.setDestinationUri(),
   DownloadManager.setDestinationInExternalPublicDir() and
   DownloadManager.addCompletedDownload() based on the latest
   storage re-design. Essentially, going forward these APIs
   will only allow downloading files into package owned dirs
   or the top-level Download dir.
-- Allow some system components to specify
   MediaColumns.OWNER_PACKAGE_NAME when inserting items into
   MediaProvider.
-- Don't copy DownloadManager.COLUMN_TITLE to MediaProvider.
   DownloadProvider and MediaProvider have different constraints
   around "title" and there isn't really a need to keep these
   in sync.
-- Sanity check file download paths hinted by apps.
-- Remove sandbox related logic in DownloadProvider.

Bug: 120879208
Bug: 128630262
Bug: 130797842

Test: manual
Test: atest DownloadProviderTests
Test: atest cts/tests/app/src/android/app/cts/DownloadManagerTest.java
Test: atest cts/tests/app/DownloadManagerLegacyTest/src/android/app/cts/DownloadManagerLegacyTest.java
Test: atest cts/tests/app/DownloadManagerApi28Test/src/android/app/cts/DownloadManagerApi28Test.java
Test: atest cts/tests/tests/provider/src/android/provider/cts/MediaStore*

Change-Id: If48bc9ecf9ed94412c6c62ce4e5e6a55fff9b789