route: rename Map to NameMap

The `Map` type is renamed to `NameMap` to better reflect what it does.

`createFromAdjLsdb` and `createFromCoordinateLsdb` functions are changed
to static functions, to match how they are used in callsites.

Unnecessary shared_ptr usage in `createFromAdjLsdb` is eliminated.

Doxygen of `NameMap` is added or improved.

refs #5308

Change-Id: I05db235efc1c6719f14b96758e3acde7826aabe7
diff --git a/src/common.hpp b/src/common.hpp
index a0db086..2076cae 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  The University of Memphis,
+ * Copyright (c) 2014-2024,  The University of Memphis,
  *                           Regents of the University of California
  *
  * This file is part of NLSR (Named-data Link State Routing).
@@ -39,21 +39,6 @@
 
 constexpr ndn::time::seconds TIME_ALLOWED_FOR_CANONIZATION = 4_s;
 
-template<typename T, typename = void>
-struct is_iterator
-{
-  static constexpr bool value = false;
-};
-
-/*! Use C++11 iterator_traits to check if some type is an iterator
- */
-template<typename T>
-struct is_iterator<T, std::enable_if_t<!std::is_same_v<
-  typename std::iterator_traits<T>::value_type, void>>>
-{
-  static constexpr bool value = true;
-};
-
 } // namespace nlsr
 
 #endif // NLSR_COMMON_HPP