Add Klocwork scanning workflows

[pcolberg]

The main branch scan obtains all Klocwork issues of the main branch and
uploads the results to a Klocwork server. This workflow requires access
to a Klocwork token to authenticate to the server for build and upload.

The pull request workflow does a full analysis of the base ref and an
incremental analysis of the head ref of the pull request using local
scans, which do not require a Klocwork server. This workflow fails if
the incremental analysis finds new issues introduced by the head ref.

[pcolberg]

This is ready for review. For the pull request workflow, I initially experimented with actions/cache for caching the Klocwork analysis of the base ref, since each full analysis takes a bit less than 5 minutes, but the workflow seemed too complex and nontrivial to maintain. Then I dropped the --rebuild option to kwcheck run, which reduces the incremental analysis of the head ref to a minute. Combined with running ninja on multiple cores under kwinject, the result is a robust, straight-forward workflow that takes a bit more than 5 minutes altogether.

[pcolberg]

Tested a passing main branch workflow accessing the Klocwork token from environment secrets, and a failing pull request workflow with an intentional issue:

fpga-runtime-for-opencl/test/acl_profiler_test.cpp

Lines 52 to 55 in d47cd93

	int *a;
	*a = 1;
	int *b = NULL;
	*b = 2;

---------------------------------------------------------------------------
182 (Local) /__w/fpga-runtime-for-opencl/fpga-runtime-for-opencl/test/acl_profiler_test.cpp:55 NPD.GEN.MUST (1:Critical) Analyze
Null pointer 'b' that comes from line 54 will be dereferenced at line 55.
  * acl_profiler_test.cpp:54: 'b' has been assigned a NULL value.
  * acl_profiler_test.cpp:55: 'b' is explicitly dereferenced.
Current status 'Analyze'

---------------------------------------------------------------------------
183 (Local) /__w/fpga-runtime-for-opencl/fpga-runtime-for-opencl/test/acl_profiler_test.cpp:53 UNINIT.STACK.MUST (1:Critical) Analyze
'a' is used uninitialized in this function.
  * acl_profiler_test.cpp:52: 'a' is declared
  * acl_profiler_test.cpp:53: 'a' is used, but is uninitialized.
Current status 'Analyze'

Summary: 2 Local
2 Total Issue(s)
Error: Process completed with exit code 1.

[zibaiwan]

Thanks Peter for your great work on this. The flow looks good to me!

[sherry-yuan]

Thank you @pcolberg, Looks good to me too.