Adds a the latest version of gBenchmark, release 1.2.0.
This is the first gBenchmark version with proper
[CMake config package installs](https://github.com/google/benchmark/issues/363).
This is important for dependencies building against it, such as gRPC.
* Add universal build_type variant to CMakePackage
* Override build_type in some packages with different possible values
* Remove reference to no longer existent debug variant
* Update CBTF packages with new build_type variant
* Keep note on build size of LLVM
* gBenchmark: Development Package
Add the development version (master branch) of `gBenchmark`
* gBenchmark: Remove Duplicate
Remove duplicate `gbenchmark` library
and keep its patch to remove the shipped
-Werror
