AutotoolsToolchain: Honor tools.apple:enable_bitcode & tools.apple:enable_arc

[SpaceIm]

Changelog: (Feature): Honor tools.apple:enable_bitcode & tools.apple:enable_arc in AutotoolsToolchain.
Docs: https://github.com/conan-io/docs/pull/XXXX

closes #12197

Similar to #10985 but for AutotoolsToolchain., except that nothing is done for tools.apple:enable_visibility because I consider that this conf is useless and doesn't make sense.
In a sense tools.apple:enable_bitcode & tools.apple:enable_arc shouldn't have been added I think, but since they are here and implemented in CMakeToolchain, conan should be consistent in all toolchains (unless you want to deprecate these conf).

Also it's worth noting that #12197 (comment) is incorrect (or not correct anymore). openssl recipe uses AutootoolsToolchain in order to collect flags for configure step.

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