Add more enums for the client and process attributes of SystemApi

For the client attribute, we have
- MODULE_APPS for representing APKs implementing modules which are
considered part of the platform
- MODULE_LIBRARIES for representing jars inside modules.

For the process attribute, we have
- SYSTEM_SERVER for representing the system_server process.

For example, @SystemApi(client=MODULE_LIBRARIES,process=ALL) actually
means that the API is meant to be available for classes in the
bootclasspath but not to the classes from the app classloader.

Bug: 140202860
Test: m

Exempt-From-Owner-Approval: cherry-picked from internal

Merged-In: Iba6a564a0967e4d109164849ee6d6500d46469de
(cherry picked from commit c524b65b55a4512ce51600aed78ee1d87f260f2b)
Change-Id: Iba6a564a0967e4d109164849ee6d6500d46469de
1 file changed
tree: f5812a6ef52fbba32f84f349d83e706c5772f112
  1. java/