Add InstallInRoot to allow modules to install into root partition

If InstallInRoot() returns true the module will be installed to
$OUT/root or $OUT/recovery/root.

Bug: 141877526
Test: m checkbuild
Test: no change to build.ninja or Android-${TARGET_PRODUCT}.mk
Test: TestPathForModuleInstall
Change-Id: Id6e435c6019f11eeb5806528fd464dbf220b88d9