feat: Generate version files and more

[uilianries]

Hello!

When consuming the project, it's hard to know what's the current library version without external references. So, in this PR I added the new feature of generating faker-cxx/Version.h automatically, based on the project version listed in CMakeLists.txt.

The same is applied for bazel, but it's duplicated (otherwise, it would complicate by a lot to extract from another file).

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Consuming Version.h may be enough in case you want to validate in runtime, but when consuming Faker-cxx via CMake, and you want to be sure about which version is available and that you want version 2.0.0, you should do:

find_package(faker-cxx 2.0.0 EXACT REQUIRED CONFIG)

CMake has no magic mechanism to detect the version, but we can export it via faker-cxxConfigVersion.cmake. So, in this PR I added too this feature, to be able to detect the project version in CMake configuration time.

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CMake is capable to generate many different types of build and dependencies scripts. Some people still use autotools + pkgconfig in Linux to build projects. For instance, if I want to know the library arguments that should be passed to my compiler, when consuming faker-cxx:

$ pkg-config --libs faker-cxx
-L/usr/local/lib -lfaker-cxx

To pkg-config be able to know that information, it needed to load the file faker-cxx.pc. That file was generated CMake, and the feature is in this pull request. So, for any cmake --build build --target install executed, CMake will install .pc file too.

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As the CMakeLists.txt is bigger and bigger, I moved divided the file, moved part of content to src/CMakeLists.txt and preserved general configuration in the root CMake file.