Generate META/apexkeys.txt

This file contains information about public/private keys of
_installed_ apexes

Details
- In GenerateAndroidBuildActions of apexBundle, prebuiltApex, apexSet,
  set a provider with the filepath of the apex's key information
- In GenerateAndroidBuildActions of androidDevice, iterate over
  `allInstalledModules`. If a module has a provider with ApexKeyInfo, it
will be concatenated to META/apexkeys.txt

Test: verified that META/apexkeys.txt is identical between make and
soong
Bug: 388633394
Change-Id: I7ac40839c0dfb6a7efabad6a8ff51f30ed393b68

Change-Id: I97c8cf82186ab47ed3ff2a647bf592a96a53b5e4