Introduce replacement for getting and setting thread name: (#4312)

* In namespace ripple, introduces get_name function that takes a
  std:🧵:native_handle_type and returns a std::string.
* In namespace ripple, introduces get_name function that takes a
  std::thread or std::jthread and returns a std::string.
* In namespace ripple::this_thread, introduces get_name function
  that takes no parameters and returns the name of the current
  thread as a std::string.
* In namespace ripple::this_thread, introduces set_name function
  that takes a std::string_view and sets the name of the current
  thread.
* Intended to replace the beast utilities setCurrentThreadName
  and getCurrentThreadName.

src/ripple/core/impl/Job.cpp

@@ -17,7 +17,7 @@
 */
 //==============================================================================
 
-#include <ripple/beast/core/CurrentThreadName.h>
+#include <ripple/basics/ThreadUtilities.h>
 #include <ripple/core/Job.h>
 #include <cassert>
 
@@ -61,7 +61,7 @@ Job::queue_time() const
 void
 Job::doJob()
 {
-    beast::setCurrentThreadName("doJob: " + mName);
+    this_thread::set_name("doJob: " + mName);
     m_loadEvent->start();
     m_loadEvent->setName(mName);