Feature: support OSX frameworks - #5552

Changelog: Feature: Better support OSX frameworks by declaring cppinfo.frameworks.
Docs: conan-io/docs#1414

closes: #5245

part 1
extend CppInfo and DepsCppInfo classes to support frameworks and framework_paths properties.
right now many of bincrafters recipes have the following code to manage frameworks:

def package_info(self):
    ...
    frameworks = ['CoreVideo', 'CoreMedia', 'CoreGraphics', 'CoreFoundation', 'OpenGL', 'Foundation']
    for framework in frameworks:
        self.cpp_info.exelinkflags.append("-framework %s" % framework)
    self.cpp_info.sharedlinkflags = self.cpp_info.exelinkflags

so, frameworks are currently managed with exelinkflags/sharedlinkflags, which is kinda ugly. proposed changes allow to write just something like:
by default, self.cpp_info.framework_paths includes rootpath, not sure if it's wise choice, need to check where frameworks are usually installed by conventions (bin vs lib vs Frameworks vs root)

def package_info(self):
    ...
    self.cpp_info.frameworks = ['CoreVideo', 'CoreMedia', 'CoreGraphics', 'CoreFoundation', 'OpenGL', 'Foundation']

part 2
set DYLD_FRAMEWORK_PATH in RunEnvironment and ConanFile.run, similar to how DYLD_LIBRARY_PATH is currently set. see https://www.manpagez.com/man/1/dyld/ for the details.

part 3
use frameworks and framework_paths in generators. right now implemented only in cmake generator via find_library - frameworks found are appended to the CONAN_LIBS.

changes were tested on SFML branch: https://github.com/bincrafters/conan-sfml/compare/framework/2.5.1?expand=1, which allows to compile frameworks instead of regular libraries via options: -o sfml:shared=True -o sfml:framework=True. as result, it creates two frameworks: SFML.framework and sfml-system.framework.

TODO:

• write some tests

• decide which directories should be used by default in self.cpp_info.framework_paths

• implement other generators (probably, xcode, compiler_args, virtualenv/virtualrunenv, other cmake_* generators)

• check if we have to change something about editable mode in case of frameworks?

• Refer to the issue that supports this Pull Request.

• If the issue has missing info, explain the purpose/use case/pain/need that covers this Pull Request.

• I've read the Contributing guide.

• I've followed the PEP8 style guides for Python code.

• I've opened another PR in the Conan docs repo to the develop branch, documenting this one.

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