Move InstallAttributes to chromeos/settings

Necessary for moving CrosSettings to chromeos/settings, so it
can eventually be used by Mustash.

The following changes were necessary:
1. Move install_attributes{.h, .cc} and unit_test.cc
2. Update c/b/chromeos/BUILD.gn (source) and chromeos/settings/BUILD.gn
(destination)
3. Update chromeos/DEPS to allow a dependency on cloud_policy_constants.h,
which is included by install_attributes.h

4. Unfortunately, that same dependency lead to a circular dependency.
I was able to avoid that by separating out a "common_constants" rule in
components/policy/core/common, so that chromeos/settings only depends on
that, and not on all of components/policy. So I had to change
components/policy/core/common/BUILD.gn
and I removed an unnecessary include from
components/policy/core/common/cloud/cloud_policy_constants.cc

5. Update #include directives for install_attributes to point to new
location. This is the other 22 files, all with diffs of +1 -1.

Bug: 446937
Change-Id: Icc8ba19c5fec91b13004b19680ead9c9f8b0a288
Reviewed-on: https://chromium-review.googlesource.com/c/1264757
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: A Olsen <olsen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599140}
30 files changed