No clang-tidy by default for external and vendor

* Most tidy-external-* and tidy-vendor-* rules
  are no longer generated. But external/bcc,
  external/android-clat, and some vendor/...
  projects still have tidy- rules because they
  have explicitly set tidy:true in .bp files.
* Some hardware/* directories are third-party
  projects and also disabled by default.

Bug: 244631413
Test: presubmit; make tidy-soong_subset
Change-Id: I17f625e6270de81a111d9cd382fbc39f34edf924