Add configurable engine features

[fmatthew5876]

Instead of querying the engine version, we can create a giant feature struct with flags for the feature differences between engines.

Examples:

• has_unlocked_picture_patch
• dual_wield_behavior - combined hit (2k), multiple hits (2k3)
• supports_reversed_states
• supports_bottom_transparency
• key_input_proc_style
• battle_system_type - 2k, 2k3
• max_actor_hp - 999 (2k), 9999 (2k3), custom value
• max_variable_value

etc..

This could be used to implement features from third party patches. It would also allow game developers to customize these for EasyRPG games.

I would add some macro and/or template magic to transform these features into compile time values. This would allow custom games to hard code their behavior and not pay any runtime costs for unsupported behaviors.

• [ ] Implement full feature set
• [ ] Add helper functions to generate feature structs from all mainstream RPG_RT versions.
• [ ] Add support for third party patch detection to enable patch features
• [ ] Add support for compile time feature set for performance

[carstene1ns]

A part of this has been implemented here: https://github.com/EasyRPG/Player/pull/2697/commits/d6584cb52e79a0e4cfa5259fbfed672f0d02c99d