feat: modernize config

- config now is more toml like
- no need to declare all fields, it implements defaults
- no yanderedev code, introspection babbyyy 😎
- desktop and config files parser semi-unification
- misc tweaks all over (mainly allocation failures handling)

include/auth.h

@@ -7,6 +7,6 @@
 #include "sessions.h"
 
 bool launch(char* user, char* passwd, struct session session, void (*cb)(void),
-            struct behavior* behavior);
+            struct config* config);
 
 #endif