Group all "bxt_remove_" stuffs into one module, add a bunch of stuffs to it, and add "bxt_clear"

[khanghugo]

closes #114

This is mainly a port of many cvars from BXT.

I want "bxt_remove_crosshair" to remove any crosshair but it only removes sprite crosshair, which Half-Life and probably every other mods use. But I want to remove CS 1.6 crosshair and it is some OpenGL drawings.

I want "bxt_remove_vgui" to remove spectator GUI in CS 1.6 but it basically disables lots of elements in the game because many elements in the games are drawn coupled with VGUI2, LOL. BXT has similar cvar and it doesn't work really well because it disables VGUI1, not VGUI2. This cvar feels very useless but many other people might find it useful (given that they have a dedicated bxt_remove_vgui 0 because removing VGUI1/2 will disable console command).

The only way to remove CS 1.6 crosshair and spectator GUI is to inject into client code.

Anyways, the rest of other cvars are okay when used with bxt_clear. With that, people don't need to inject BXT to do green screen stuffs.

[Copilot]

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

src/modules/remove_stuffs.rs:9

• [nitpick] Consider using a more descriptive name than 'RemoveStuffs' (e.g., 'RemoveVisualElements' or 'DisplayRemoval') to more clearly indicate the module's purpose.

pub struct RemoveStuffs;

src/modules/remove_stuffs.rs:16

• [nitpick] The description 'Removing visible stuffs from the game' could be made more precise—for example, 'Removing visual elements from the game'—to enhance clarity.

fn description(&self) -> &'static str {