Prepare for boost::url upgrade

The new boost URL now interops properly with std::string_view, which is
great, and cleans up a bunch of mediocre code to convert one to another.
It has also been pulled into boost-proper, so we no longer need a
boost-url dependency that's separate.

Unfortunately, boost url makes these improvements by changing
boost::string_view for boost::urls::const_string, which causes us to
have some compile errors on the missing type.

The bulk of these changes fall into a couple categories, and have to be
executed in one commit.
string() is replaced with buffer() on the url and url_view types
boost::string_view is replaced by std::string_view for many times, in
many cases removing a temporary that we had in the code previously.

Tested: Code compiles with boost 1.81.0 beta.
Redfish service validator passes.
Pretty good unit test coverage for URL-specific use cases.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I8d3dc89b53d1cc390887fe53605d4867f75f76fd
diff --git a/redfish-core/include/utils/collection.hpp b/redfish-core/include/utils/collection.hpp
index 97f622d..f117302 100644
--- a/redfish-core/include/utils/collection.hpp
+++ b/redfish-core/include/utils/collection.hpp
@@ -29,7 +29,7 @@
                          const char* subtree = "/xyz/openbmc_project/inventory")
 {
     BMCWEB_LOG_DEBUG << "Get collection members for: "
-                     << collectionPath.string();
+                     << collectionPath.buffer();
     crow::connections::systemBus->async_method_call(
         [collectionPath, aResp{std::move(aResp)}](
             const boost::system::error_code ec,