Integrate libcpp compilation into CI

[123R3N321]

As described in PR #976 , we will need to get CI integration to pass the cpp tests

[123R3N321]

further discussion with @tashabits , clearly there is more work to be done with the CI pipeline. Here are the changes I propose to make:

• Separate the changes to scripts/lind_compile (re-purposing from clang to clang++) from the original to a separate, new script, tentatively placed at the same directory level as the original and to be named lind_compile_cpp (.sh file)

• Add modifications to the CI flow, one option is in particular somewhere along the existing e2e call chain of e3e.yml -> dockerfile.e2e-> Makefile->test_runner.py->check_reports.py. I think this is really complicated (and I do not want to mess up the existing report generating), I propose to simply add one more .yml that executes smoke test with .cpp dummy file compilation (using the existing trial/hello.cpp, which is to be moved into a different directory more appropriate soon) and instead of report file export, it will be very verbose in the github CI flow report on the browser. This will be essentially a new module to the existing CI flow.

• Add, and git track, pre-built archive file(s) for clang++ compilation, this should eliminate the need of llvm in the repo all together

• Update relevant documentation on above changes

• Apply minor fix on lind_compile script. There is a flag I missed and pointed out by Alice.

Please let me know if there are any flaws or missing steps in what I propose here. @tashabits @Yaxuan-w @rennergade

[123R3N321]

now that dynamic loading is added, I might be able to move away from dependencies on the static .a archives all together. This is worth looking into.