Move BasePermission to own package

This is the first of many changes. Moving permissions to their own package.

Change-Id: I60e94e2da3c96788fc165e97e813ab5b9ee51586
Bug: 63539144
Test: Manual. Builds and runs
Test: cts-tradefed run commandAndExit cts-dev -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.PermissionsHostTest
Test: cts-tradefed run commandAndExit cts-dev -m CtsPermissionTestCases
Test: cts-tradefed run commandAndExit cts-dev -m CtsPermission2TestCases