internal: introduce new types to avoid unsigned int rollover and signed int overflow (#7216)

* framebuffer: avoid gluint overflow

GLuint was being initialized to -1 and rolling over to unsigned int max,
its defined behaviour but very unnecessery. add a bool and use it for
checking if allocated or not.

* opengl: avoid gluint rollover

-1 rolls over to unsigned int max, use 0xFF instead.

* core: big uint64_t to int type conversion

there were a few uint64_t to int implicit conversions overflowing int
and causing UB, make all monitor/workspaces/windows use the new
typedefs. also fix the various related 64 to 32 implicit conversions
going around found with -Wshorten-64-to-32

src/config/ConfigManager.cpp

@@ -2425,7 +2425,7 @@ std::optional<std::string> CConfigManager::handleWorkspaceRules(const std::strin
     // }
 
     const static std::string ruleOnCreatedEmpty    = "on-created-empty:";
-    const static int         ruleOnCreatedEmptyLen = ruleOnCreatedEmpty.length();
+    const static auto        ruleOnCreatedEmptyLen = ruleOnCreatedEmpty.length();
 
     auto                     assignRule = [&](std::string rule) -> std::optional<std::string> {
         size_t delim = std::string::npos;