[grpc] Use protos and binaries from requirements googleapis and grpc-proto (RFC)

[jgsogo]

Here I'm proposing some patches to consume headers and libraries from googleapis and grpc-proto instead of generating and building them in grpc itself. In any case there are some protos that need to be generated while building grpc because they use grpc_cpp_plugin (utility like protoc) that is built in the grpc project.

With this approach, I try to prevent ODR violations when consumers of grpc need to use some protos from googleapis (I'm looking at you, google-cloud-cpp project). It will also ensure that all the graph is using the same protos (and files generated from them).

Finally, the patches were not as complicated as I had feared 😃

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Big question: is it worth the effort? Is it adding too much complexity to the project?

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TODO:

• Pending grpc-proto - Build project and libraries (CMake auto generated) #11827

[ericLemanissierBot]

I detected other pull requests that are modifying grpc/all recipe:

• bubmpup grpc protobuf dependency to 3.21.4 #12157
• [gRPC] Enable the tests building from the Conan package #10804

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[conan-center-bot]

All green in build 7 (3be57705260db42696b3be9ed4a2a1cd3a255203):

• grpc/1.48.0@:
  All packages built successfully! (All logs)

  🔸 Informative: This recipe is not ready for Conan v2

  _{We have started the migration process to Conan v2 and exporting recipes successfully will be required in the future.
  This is just an informative note to gain awareness about the process, no need to take any action. The plan is to enforce smaller steps that are easier to fix and, eventually, this conan export step will work.
  See the recipe migration guide to know more about the changes required.}

  ERROR: Error loading conanfile at '/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py': Unable to load conanfile in /home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py", line 4, in <module>
      from conans import ConanFile, CMake, tools as tools_legacy
  ImportError: cannot import name 'ConanFile' from 'conans' (/opt/pyenv/versions/3.7.13/lib/python3.7/site-packages/conans/__init__.py)
  

• grpc/1.46.3@:
  All packages built successfully! (All logs)

  🔸 Informative: This recipe is not ready for Conan v2

  _{We have started the migration process to Conan v2 and exporting recipes successfully will be required in the future.
  This is just an informative note to gain awareness about the process, no need to take any action. The plan is to enforce smaller steps that are easier to fix and, eventually, this conan export step will work.
  See the recipe migration guide to know more about the changes required.}

  ERROR: Error loading conanfile at '/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py': Unable to load conanfile in /home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py", line 4, in <module>
      from conans import ConanFile, CMake, tools as tools_legacy
  ImportError: cannot import name 'ConanFile' from 'conans' (/opt/pyenv/versions/3.7.13/lib/python3.7/site-packages/conans/__init__.py)
  

• grpc/1.47.1@:
  All packages built successfully! (All logs)

  🔸 Informative: This recipe is not ready for Conan v2

  _{We have started the migration process to Conan v2 and exporting recipes successfully will be required in the future.
  This is just an informative note to gain awareness about the process, no need to take any action. The plan is to enforce smaller steps that are easier to fix and, eventually, this conan export step will work.
  See the recipe migration guide to know more about the changes required.}

  ERROR: Error loading conanfile at '/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py': Unable to load conanfile in /home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/w/prod_cci_PR-12062/recipes/grpc/all/conanfile.py", line 4, in <module>
      from conans import ConanFile, CMake, tools as tools_legacy
  ImportError: cannot import name 'ConanFile' from 'conans' (/opt/pyenv/versions/3.7.13/lib/python3.7/site-packages/conans/__init__.py)