gchimp_info reuse and anything entity related

[khanghugo]

At the moment, there are two gchimp functionalities using entities in-editor: map2mdl and rename_texture. The way gchimp works on .map along with the editor is that editor will call gchimp binary with selected features. Basically just how gchimp CLI should work.

map2mdl has an entity encompassing all gchimp settings: gchimp_info. So far, this entity is only meant for map2mdl and even its codebase is contained within the module. Need to consider if this entity should do what it should do. With that, users can load gchimp with all functionalities with selected order and then enable or disable features as they want by toggling the entity rather than the compile process.

gchimp_info should be its own module and other modules using entities should depend on it. Matter of fact, while at it, gchimp should also have its own FGD library, capable of generating FGD file according to modules interact-able through in-editor entities.

So, the plan is:

• gchimp_info should be its own module
• Toggling any gchimp functionality should go through gchimp_info
• The user only needs to enable functionality and forget about it when they setup the compile process. They will not need to toggle the compile process.
• FGD library
• An interface that works with FGD library to describe entity and autogenerate FGD. This implicates a lot of work to refactor map2mdl (very complicated code) to follow pattern.

It is a nice to have and will save lots of time in the future. REMEC in Rust.