Use rules_foreign_cc to build libcurl

[coryan]

Assuming we want to continue building libcurl from source for Bazel-based builds, we should move these to use rules_foreign_cc, and build using the CMake files distributed with libcurl instead of our own (and hacky) BUILD file.

[coryan]

I gave this a try, in an attempt to fix #7462. It turns out to be more finicky than I expected, here are some notes to save time on the next attempt:

• gRPC depends on c-ares and provides its own cares.BUILD file. To avoid having two cares (aka c-ares) libraries we have to pick which one to use. Compiling c-ares with rules_foreign_cc() seems to make gRPC unhappy.
• rules_foreign_cc() hard-codes the destination directory of libraries to $prefix/lib/. The correct directory depends on the distro, and one needs to hard-code the path in the CMake invocation.
• It seems that most of the examples showing how to use rules_foreign_cc() require Bazel >= 4.2, we would need to port the BUILD.${lib}.bazel files to Bazel 3.5
• Bazel treats a CMake invocation as a single command, and does not expect to execute tasks in parallel. At times Bazel is running $(nproc) tasks and cmake is running another $(nproc) tasks.
• Any use of *san is not passed down to the libraries built with rules_foreign_cc(), for the most part this is harmless, it might produce false negatives (or false positives?) with msan.

foreign.patch.txt

[coryan]

Close it for now, if there is a problem with the custom rule we can reopen.