refactor: introduce a more general LockDirectories for init

No functional change. This is in preparation for adding additional directory
locks on startup.

src/node/interfaces.cpp

@@ -116,7 +116,7 @@ public:
         m_context->ecc_context = std::make_unique<ECC_Context>();
         if (!AppInitSanityChecks(*m_context->kernel)) return false;
 
-        if (!AppInitLockDataDirectory()) return false;
+        if (!AppInitLockDirectories()) return false;
         if (!AppInitInterfaces(*m_context)) return false;
 
         return true;