core: Add clang-tidy (#8664)

This adds a .clang-tidy file for us.

It's not a strict requirement to be compliant, but I tuned it to be alright.

src/managers/KeybindManager.hpp

@@ -3,7 +3,6 @@
 #include "../defines.hpp"
 #include <deque>
 #include <set>
-#include "../Compositor.hpp"
 #include <unordered_map>
 #include <functional>
 #include <xkbcommon/xkbcommon.h>
@@ -15,6 +14,8 @@ class CConfigManager;
 class CPluginSystem;
 class IKeyboard;
 
+enum eMouseBindMode : int8_t;
+
 struct SKeybind {
     std::string            key            = "";
     std::set<xkb_keysym_t> sMkKeys        = {};
@@ -42,7 +43,7 @@ struct SKeybind {
     bool shadowed = false;
 };
 
-enum eFocusWindowMode {
+enum eFocusWindowMode : uint8_t {
     MODE_CLASS_REGEX = 0,
     MODE_INITIAL_CLASS_REGEX,
     MODE_TITLE_REGEX,
@@ -67,7 +68,7 @@ struct SParsedKey {
     bool        catchAll = false;
 };
 
-enum eMultiKeyCase {
+enum eMultiKeyCase : uint8_t {
     MK_NO_MATCH = 0,
     MK_PARTIAL_MATCH,
     MK_FULL_MATCH