CMake: Use LAPACK imported target

[gardner48]

1. Use LAPACK::LAPACK rather than LAPACK_LIBRARIES
2. Simplify try_compile test
3. Don't overwrite LAPACK_WORKS (test every configuration pass)
4. Use CHECK_START, CHECK_PASSED, and CHECK_FAILED messages in compile test
5. Replace manual include guard with include_guard(GLOBAL)
6. Update SundialsTPL.cmake.template with above changes

[gardner48]

This may help address #350.

[gardner48]

@balos1 If you're good with the updates to SundialsTPL.cmake.template and LAPACK_WORKS, I'll see about propagating these changes to the other TPL files (in follow on PRs).

With LAPACK_WORKS this is now only used to bypass the compile test and not to indicate if the compile test passed (since failing is a fatal error). So _WORKS might not be the best name, maybe LAPACK_TEST or SUNDIALS_LAPACK_TEST or SUN_LAPACK_TEST (for better namespacing).