[DO NOT MERGE] Rollup changes from R related to CertInstaller and KeyChain

This change includes the following commits that are related to
CertInstaller and KeyChain:

7a5c8fe4afd KeyChain: Unify manual and programmatic key installation flows
a894225c7da Added functionality to select type of certificate to be installed from the Settings app
a9131939a35 Add KeyChain.KEY_ALIAS_SELECTION_DENIED constant.
485be505f19 Fix KeyChain.KEY_ALIAS_SELECTION_DENIED

Bug: 161347472
Test: builds & manual testing
Change-Id: I560bade479b41a5b88f81ea6dfdecba689c2f4ad