Do not install required modules from order-only deps

When a vintf_fragments or init_rc file is shared by two modules,
unintended modules are installed due to the shared file.

This was caused by add-all-target-to-target-required-modules-deps.

With the following definitions:

cc_binary {
  name: "foo",
  vintf_fragments: ["shared.xml"],
  required: ["foo-req"],
}

cc_binary {
  name: "bar",
  vintf_fragments: ["shared.xml"],
}

When installing "bar", surprisingly, "foo-req" is installed due to the
link between "shared.xml" and "foo-req" added by
add-all-target-to-target-required-modules-deps.

To fix that, in this change, vintf_fragments and init_rc files are
marked as "order-only" deps. In
add-all-target-to-target-required-modules-deps, order-only deps are not
used to add links to "required" modules.

Now, with the same definitions, installing "bar" won't installs
"foo-req".

Bug: 198818343
Test: (see above)
Change-Id: I16be0dcb84564c559cb2f4223e2812321ee14729