impr: Refactor and restructure Event Manager (#2082)

### Problem description
This PR addresses issue #2013 that described a cluttered Event Manager.

This is a DX issue and should not impact the users whatsoever.

### Implementation description
The changes revolve around three main points:

1. the Event Manager (`event_manager.hpp`) was split into four
categories: GUI, Interaction, Lifecycle, and Provider, and two types:
Events, and Requests. This results in the following files:
    - `events_gui.hpp`
    - `events_interaction.hpp`
    - `events_lifecycle.hpp`
    - `events_provider.hpp`
    - `requests_gui.hpp`
    - `requests_interaction.hpp`
    - `requests_lifecycle.hpp`
    - `requests_provider.hpp`

2. Every event and request now has its own piece of documentation, with
a `@brief`, accompanied by a longer comment if needed, and gets its
`@param`s described.

3. The old `event_manager.hpp` import was removed and replaced by the
correct imports wherever needed, as to reduce spread of those files only
to where they are truly useful.

### Additional things
The commits have been split into (chrono-)logical steps:
- `feat`: split the Event Manager, and replace the imports
- `refactor`, `chore`: make various small changes to match the required
structure
- `docs`: add documentation for events and requests

Hopefully, this will help to review the PR.
*Note: Beware of very long rebuild times in between the commits, use
them sparingly! The Actions will ensure this PR builds anyways*

Closes #2013

---------

Signed-off-by: BioTheWolff <47079795+BioTheWolff@users.noreply.github.com>
Co-authored-by: Nik <werwolv98@gmail.com>

main/gui/source/init/run/common.cpp

@@ -1,4 +1,4 @@
-#include <hex/api/event_manager.hpp>
+#include <hex/api/events/requests_interaction.hpp>
 #include <hex/api/task_manager.hpp>
 #include <hex/helpers/utils.hpp>
 

main/gui/source/init/run/native.cpp

@@ -1,6 +1,6 @@
 #if !defined(OS_WEB)
 
-    #include <hex/api/event_manager.hpp>
+    #include <hex/api/events/requests_lifecycle.hpp>
     #include <wolv/utils/guards.hpp>
 
     #include <init/run.hpp>

main/gui/source/init/run/web.cpp

@@ -4,7 +4,7 @@
     #include <emscripten/html5.h>
 
     #include <hex/api/imhex_api.hpp>
-    #include <hex/api/event_manager.hpp>
+    #include <hex/api/events/requests_lifecycle.hpp>
     #include <hex/api/task_manager.hpp>
 
     #include <window.hpp>

main/gui/source/init/splash_window.cpp

@@ -2,7 +2,7 @@
 #include "init/splash_window.hpp"
 
 #include <hex/api/imhex_api.hpp>
-#include <hex/api/event_manager.hpp>
+#include <hex/api/events/requests_lifecycle.hpp>
 
 #include <hex/helpers/utils.hpp>
 #include <hex/helpers/fmt.hpp>

main/gui/source/messaging/common.cpp

@@ -1,7 +1,8 @@
 #include <optional>
 
 #include <hex/api/imhex_api.hpp>
-#include <hex/api/event_manager.hpp>
+#include <hex/api/events/events_lifecycle.hpp>
+#include <hex/api/events/requests_lifecycle.hpp>
 #include <hex/helpers/logger.hpp>
 
 #include "messaging.hpp"

main/gui/source/window/linux_window.cpp

@@ -4,7 +4,8 @@
 
     #include <hex/api/imhex_api.hpp>
     #include <hex/api/content_registry.hpp>
-    #include <hex/api/event_manager.hpp>
+    #include <hex/api/events/events_gui.hpp>
+    #include <hex/api/events/requests_gui.hpp>
 
     #include <hex/helpers/utils.hpp>
     #include <hex/helpers/utils_linux.hpp>

main/gui/source/window/macos_window.cpp

@@ -4,7 +4,8 @@
 
     #include <hex/api/project_file_manager.hpp>
     #include <hex/api/imhex_api.hpp>
-    #include <hex/api/event_manager.hpp>
+    #include <hex/api/events/events_gui.hpp>
+    #include <hex/api/events/requests_gui.hpp>
     #include <hex/api/task_manager.hpp>
 
     #include <hex/helpers/utils_macos.hpp>

main/gui/source/window/web_window.cpp

@@ -5,7 +5,9 @@
 #include <emscripten.h>
 #include <emscripten/html5.h>
 
-#include <hex/api/event_manager.hpp>
+#include <hex/api/events/events_gui.hpp>
+#include <hex/api/events/events_interaction.hpp>
+#include <hex/api/events/requests_gui.hpp>
 
 #include <imgui.h>
 #include <imgui_internal.h>

main/gui/source/window/win_window.cpp

@@ -12,6 +12,9 @@
     #include <hex/helpers/logger.hpp>
     #include <hex/helpers/default_paths.hpp>
 
+    #include <hex/api/events/events_gui.hpp>
+    #include <hex/api/events/requests_gui.hpp>
+
     #include <imgui.h>
     #include <imgui_internal.h>
 

main/gui/source/window/window.cpp

@@ -9,6 +9,10 @@
 #include <hex/api/shortcut_manager.hpp>
 #include <hex/api/workspace_manager.hpp>
 #include <hex/api/tutorial_manager.hpp>
+#include <hex/api/events/requests_lifecycle.hpp>
+#include <hex/api/events/events_lifecycle.hpp>
+#include <hex/api/events/requests_gui.hpp>
+#include <hex/api/events/events_gui.hpp>
 
 #include <hex/helpers/utils.hpp>
 #include <hex/helpers/logger.hpp>