[develop2] Simplifying the Options model

[memsharded]

Changelog: Omit
Docs: Omit

New proposal to simplify Options:

• Remove the OptionValues, PkgOptionValues, PkgOptionValue classes that duplicate too much of the model, making it way more complex.
• Isolated the implementation, the only public interface to options is now the Options class
• Some simplifications in the Options class and its collaborators
• Changed how options are propagated in the graph, separating the options that are modified by downstream dependencies from the options that are self-defined or defined by profiles, because that massively affects things like build-order
• This change in propagation should help to prepare for better propagation in the "build" context. This might still need some new model, like build_options in recipes, but that will follow in another PR
• Changes in the conaninfo.txt now are very minimal, just derived from the fact that not all options from dependencies are stored there now. This will change, but in a following PR, to keep this more focused.

Close #9900

[lasote]

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