Profiler: Move everything into the "Profiler" namespace

Userland/DevTools/Profiler/SamplesModel.cpp

@@ -9,6 +9,8 @@
 #include <AK/StringBuilder.h>
 #include <stdio.h>
 
+namespace Profiler {
+
 SamplesModel::SamplesModel(Profile& profile)
     : m_profile(profile)
 {
@@ -91,3 +93,5 @@ void SamplesModel::update()
 {
     did_update(Model::InvalidateAllIndices);
 }
+
+}