Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 3.5.
Note that the effective policy version includes `...<max>` treatment.
Update the check from commit 5845c218d7 (Deprecate compatibility with
CMake versions older than 2.8.12, 2020-06-12, v3.19.0-rc1~629^2).

For policy-specific tests, use the version before the policy was
introduced.  Otherwise, use 3.5 where possible.

Also, remove `cmake_minimum_required()` and `project()` calls from
individual cases where they are handled by `CMakeLists.txt`.

The OLD behaviors of all policies are deprecated, but only by
documentation.  Add an explicit deprecation diagnostic for policies
introduced in CMake 3.18 and below to encourage projects to port
away from setting policies to OLD.

Previously items linked via the link interface of a dependency were
reported in CMP0028 messages as if directly linked by a target.
Clarify the messages to indicate that an offending item is actually
in the link interface of a given target, regardless of its consumer.

Move the check to the end of generation and look through the final set
of link implementations and link interfaces that were used for
generation.  This avoids repeating messages on link interfaces that
have multiple consumers.

Now that we have proper backtraces for both `LINK_LIBRARIES` and
`INTERFACE_LINK_LIBRARIES` entries, we can report them in error
messages.

The OLD behaviors of all policies are deprecated, but only by
documentation.  Add an explicit deprecation diagnostic for policies
introduced in CMake 3.13 and below to encourage projects to port
away from setting policies to OLD.

Previously we would synthesize <TARGET_NAME>-NOTFOUND as the location. This
would then end up on the link line and cause build failures.
Policy CMP0110 is added to control this behaviour.

Fixes #19080, #19943.

Use 3.3 or 2.8.12 where possible.

Fixes: #20836

Fixes: #20641